Email History and facts

Email
This article is about the communications medium. For
the former manufacturing conglomerate, see Email Limited.
“Inbox” redirects here. For the Google product, see
Google Inbox.
Electronic mail, most commonly referred to as email or

and a message submission date/time stamp.
Originally a text-only (ASCII) communications medium,
Internet email was extended to carry, e.g. text in other
character sets, multi-media content attachments, a process standardized in RFC 2045 through 2049. Collectively, these RFCs have come to be called Multipurpose
Internet Mail Extensions (MIME). Subsequent RFCs
have proposed standards for internationalized email addresses using UTF-8.
Electronic mail predates the inception of the Internet and
was in fact a crucial tool in creating it,[5] but the history of
modern, global Internet email services reaches back to the
early ARPANET. Standards for encoding email messages
were proposed as early as 1973 (RFC 561). Conversion
from ARPANET to the Internet in the early 1980s produced the core of the current services. An email message
sent in the early 1970s looks quite similar to a basic text
message sent on the Internet today.
Email is an information and communications technology.
It uses technology to communicate a digital message over
the Internet. Users use email differently, based on how
they think about it. There are many software platforms
available to send and receive. Popular email platforms include Gmail, Hotmail, Yahoo! Mail, Outlook, and many
others.[6]

The at sign, a part of every SMTP email address.[1]

Network-based email was initially exchanged on the
ARPANET in extensions to the File Transfer Protocol
(FTP), but is now carried by the Simple Mail Transfer
Protocol (SMTP), first published as Internet standard 10
(RFC 821) in 1982. In the process of transporting email
messages between systems, SMTP communicates delivery parameters using a message envelope separate from
the message (header and body) itself.

e-mail since c 1993,[2] is a method of exchanging digital
messages from an author to one or more recipients. Modern email operates across the Internet or other computer
networks. Some early email systems required the author
and the recipient to both be online at the same time, in
common with instant messaging. Today’s email systems
are based on a store-and-forward model. Email servers
accept, forward, deliver, and store messages. Neither the
users nor their computers are required to be online simultaneously; they need connect only briefly, typically
to a mail server, for as long as it takes to send or receive messages. Historically, the term electronic mail was
used generically for any electronic document transmission. For example, several writers in the early 1970s used
the term to describe fax document transmission.[3][4] As
a result, it is difficult to find the first citation for the use
of the term with the more specific meaning it has today.

1 Spelling
Electronic mail has several English spelling options that
occasionally are the cause of vehement disagreement.
• e-mail is the most common form. According to
Corpus of Contemporary American English data,
this is the form that appears most frequently in
edited, published American English and British English writing.[7]

An Internet email message consists of three components,
the message envelope, the message header, and the message body. The message header contains control information, including, minimally, an originator’s email address
and one or more recipient addresses. Usually descriptive
information is also added, such as a subject header field

• email is the most common form used online,
and is required by IETF Requests for Comments
1

2

2 ORIGIN
and working groups[8] and increasingly by style
guides.[9][10][11] This spelling also appears in most
dictionaries.[12][13][14][15][16][17][18]
• mail was the form used in the original RFC. The
service is referred to as mail, and a single piece of
electronic mail is called a message.[19][20][21]
• EMail is a traditional form that has been used in
RFCs for the “Author’s Address”[20][21] and is expressly required “for historical reasons”.[22]
• E-mail is sometimes used, capitalizing the initial E
as in similar abbreviations like E-piano, E-guitar, Abomb, and H-bomb.[23]

2

Origin

• 1978 – Mail client written by Kurt Shoens for Unix
and distributed with the Second Berkeley Software
Distribution included support for aliases and distribution lists, forwarding, formatting messages, and
accessing different mailboxes.[38] It used the Unix
mail client to send messages between system users.
The concept was extended to communicate remotely
over the Berkley Network.[39]
• 1979 – EMAIL written by V.A. Shiva Ayyadurai to
emulate the interoffice mail system of the University
of Medicine and Dentistry of New Jersey[40][41]
• 1979 – MH Message Handling System developed
at RAND provided several tools for managing electronic mail on Unix.[42]
• 1981 – PROFS by IBM[43][44]
• 1982 – ALL-IN-1[45] by Digital Equipment Corporation

The AUTODIN network, first operational in 1962, provided a message service between 1,350 terminals, handling 30 million messages per month, with an average
message length of approximately 3,000 characters. Autodin was supported by 18 large computerized switches,
and was connected to the United States General Services Administration Advanced Record System, which
provided similar services to roughly 2,500 terminals.[24]

These original messaging systems had widely different
features and ran on systems that were incompatible with
each other. Most of them only allowed communication
between users logged into the same host or “mainframe”,
although there might be hundreds or thousands of users
within an organization.

2.1

2.2 LAN email systems

Host-based mail systems

With the introduction of MIT's Compatible TimeSharing System (CTSS) in 1961[25] multiple users were
able to log into a central system[26] from remote dialup terminals, and to store and share files on the central
disk.[27] Informal methods of using this to pass messages
were developed and expanded :
• 1965 – MIT's CTSS MAIL.[28]
Developers of other early systems developed similar
email applications:
• 1962 – 1440/1460 Administrative Terminal System[29]
• 1968 – ATS/360[30][31]

In the early 1980s, networked personal computers on
LANs became increasingly important. Server-based systems similar to the earlier mainframe systems were developed. Again, these systems initially allowed communication only between users logged into the same server
infrastructure. Examples include:
• cc:Mail
• Lantastic
• WordPerfect Office
• Microsoft Mail
• Banyan VINES
• Lotus Notes

Eventually these systems too could link different orga• 1971 – SNDMSG, a local inter-user mail program nizations as long as they ran the same email system and
incorporating the experimental file transfer pro- proprietary protocol.[46]
gram, CPYNET, allowed the first networked electronic mail[32]
• 1972 – Unix mail program[33][34]

2.3 Email networks

To facilitate electronic mail exchange between remote
sites and with other organizations, telecommunication
• 1974 – The PLATO IV Notes on-line message links, such as dialup modems or leased lines, provided
board system was generalized to offer 'personal means to transport email globally, creating local and
notes’ in August 1974.[24][37]
global networks.
• 1972 – APL Mailbox by Larry Breed[35][36]

2.5

From SNDMSG to MSG

• In 1971 the first ARPANET email was sent,[47] and
through RFC 561, RFC 680, RFC 724, and finally
1977’s RFC 733, became a standardized working
system.

3
• X.400 in the 1980s and early 1990s was promoted
by major vendors, and mandated for government use
under GOSIP, but abandoned by all but a few in favor of Internet SMTP by the mid-1990s.

• PLATO IV was networked to individual terminals
over leased data lines prior to the implementation of
personal notes in 1974.[37]
2.5

From SNDMSG to MSG

• Unix mail was networked by 1978’s uucp,[48] which
In the early 1970s, Ray Tomlinson updated an existwas also used for USENET newsgroup postings
ing utility called SNDMSG so that it could copy mes• BerkNet, the Berkeley Network, written by Eric sages (as files) over the network. Lawrence Roberts The
Schmidt in 1978 and included first in the Second project manager for the ARPANET development, took
Berkeley Software Distribution provided support for the idea of READMAIL, which dumped all “recent” messending and receiving messages over serial commu- sages onto the user’s terminal, and wrote a programme
nication links. The Unix mail tool was extended to for TENEX in TECO macros called RD, which permitted access to individual messages.[55] Barry Wessler then
send messages using BerkNet.[39]
updated RD and called it NRD.[56]
• The delivermail tool written by Eric Allman in 1979
and 1980 (and shipped in 4BSD) provided support Marty Yonke rewrote NRD to include reading, access
for routing mail over different networks including to SNDMSG for sending, and a help system, and called
Arpanet, UUCP, and BerkNet. (It also provided the utility WRD, which was later known as BANANARD.
John Vittal then updated this version to include three imsupport for mail user aliases.)[49]
portant commands: Move (combined save/delete com• The mail client included in 4BSD (1980) was ex- mand), Answer (determined to whom a reply should be
tended to provide interoperability between a variety sent) and Forward (sent an email to a person who was
not already a recipient). The system was called MSG.
of mail systems.[50]
With inclusion of these features, MSG is considered to
• BITNET (1981) provided electronic mail services be the first integrated modern email programme, from
for educational institutions. It was based on the IBM which many other applications have descended.[55]
VNET email system.[51]
• In 1984, IBM PCs running DOS could link with
FidoNet for email and shared bulletin board post- 2.6
ing.

2.4

Attempts at interoperability

Early interoperability among independent systems included:
• ARPANET, a forerunner of the Internet, defined
protocols for dissimilar computers to exchange
email.

ARPANET mail

Experimental email transfers between separate computer
systems began shortly after the creation of the ARPANET
in 1969.[28] Ray Tomlinson is generally credited as having
sent the first email across a network, initiating the use
of the "@" sign to separate the names of the user and
the user’s machine in 1971, when he sent a message from
one Digital Equipment Corporation DEC-10 computer to
another DEC-10. The two machines were placed next to
each other.[32][57] Tomlinson’s work was quickly adopted
across the ARPANET, which significantly increased the
popularity of email. For many years, email was the killer
app of the ARPANET and then the Internet.

• uucp implementations for Unix systems, and later
for other operating systems, that only had dial-up
communications available.
As the influence of the ARPANET and later the Internet grew, gateways were developed to pass mail between
• CSNET, which initially used the UUCP protocols
it and other networks such as JANET, BITNET, X.400,
via dial-up to provide networking and mail-relay serFidoNet, and UUCP. This often involved addresses such
vices for non-ARPANET hosts.
as:
• Novell developed the Message Handling System hubhost!middlehost!edgehost!user@uucpgateway.somedomain.example.com
(MHS) protocol[52][53][54] but abandoned it after
purchasing the non-MHS WordPerfect Office (re- Despite the complex format of some such addresses, (in
this case an Internet email address to route mail to a user
named Groupwise)
with a "bang path" address at a UUCP host), they did
• The Coloured Book protocols on UK academic net- lead to the universal connectivity that is the key feature
works until 1992
of modern email.

4

3

4

Operation overview

The diagram to the right shows a typical sequence of
events[58] that takes place when Alice composes a message using her mail user agent (MUA). She enters the
email address of her correspondent, and hits the “send”
button.
1. Her MUA formats the message in email format
and uses the Submission Protocol (a profile of the
Simple Mail Transfer Protocol (SMTP), see RFC
6409) to send the message to the local mail submission agent (MSA), in this case smtp.a.org, run by
Alice’s internet service provider (ISP).
2. The MSA looks at the destination address provided in the SMTP protocol (not from the message header), in this case [email protected]. An Internet email address is a string of the form localpart@exampledomain. The part before the @ sign
is the local part of the address, often the username
of the recipient, and the part after the @ sign is
a domain name or a fully qualified domain name.
The MSA resolves a domain name to determine the
fully qualified domain name of the mail server in the
Domain Name System (DNS).
3. The DNS server for the b.org domain, ns.b.org,
responds with any MX records listing the mail
exchange servers for that domain, in this case
mx.b.org, a message transfer agent (MTA) server
run by Bob’s ISP.
4. smtp.a.org sends the message to mx.b.org using
SMTP.

MESSAGE FORMAT

Internet mail gateway which also does any necessary
reformatting. If Alice and Bob work for the same
company, the entire transaction may happen completely within a single corporate email system.
• Alice may not have a MUA on her computer but instead may connect to a webmail service.
• Alice’s computer may run its own MTA, so avoiding
the transfer at step 1.
• Bob may pick up his email in many ways, for example logging into mx.b.org and reading it directly, or
by using a webmail service.
• Domains usually have several mail exchange servers
so that they can continue to accept mail when the
main mail exchange server is not available.
• Email messages are not secure if email encryption
is not used correctly.
Many MTAs used to accept messages for any recipient on
the Internet and do their best to deliver them. Such MTAs
are called open mail relays. This was very important in the
early days of the Internet when network connections were
unreliable. If an MTA couldn't reach the destination, it
could at least deliver it to a relay closer to the destination.
The relay stood a better chance of delivering the message
at a later time. However, this mechanism proved to be
exploitable by people sending unsolicited bulk email and
as a consequence very few modern MTAs are open mail
relays, and many MTAs don't accept messages from open
mail relays because such messages are very likely to be
spam.

4 Message format

This server may need to forward the message to other
MTAs before the message reaches the final message deThe Internet email message format is now defined by
livery agent (MDA).
RFC 5322, with multi-media content attachments being
defined in RFC 2045 through RFC 2049, collectively
1. The MDA delivers it to the mailbox of the user bob. called Multipurpose Internet Mail Extensions or MIME.
RFC 5322 replaced the earlier RFC 2822 in 2008, and
2. Bob presses the “get mail” button in his MUA, which
in turn RFC 2822 in 2001 replaced RFC 822 – which
picks up the message using either the Post Office
had been the standard for Internet email for nearly 20
Protocol (POP3) or the Internet Message Access
years. Published in 1982, RFC 822 was based on the
Protocol (IMAP).
earlier RFC 733 for the ARPANET.[59]
That sequence of events applies to the majority of email Internet email messages consist of two major sections:
users. However, there are many alternative possibilities
• Header – Structured into fields such as From, To,
and complications to the email system:
CC, Subject, Date, and other information about the
email.
• Alice or Bob may use a client connected to a cor• Body – The basic content, as unstructured text;
porate email system, such as IBM Lotus Notes or
sometimes containing a signature block at the end.
Microsoft Exchange. These systems often have their
This is exactly the same as the body of a regular letown internal email format and their clients typically
ter.
communicate with the email server using a vendorspecific, proprietary protocol. The server sends or
receives email via the Internet through the product’s The header is separated from the body by a blank line.

4.1

4.1

Message header

5

Message header

provisional message header field names, including also
fields defined for MIME, netnews, and http, and referEach message has exactly one header, which is structured encing relevant RFCs. Common header fields for email
into fields. Each field has a name and a value. RFC 5322 include:[66]
specifies the precise syntax.
Informally, each line of text in the header that begins with
a printable character begins a separate field. The field
name starts in the first character of the line and ends before the separator character ":". The separator is then
followed by the field value (the “body” of the field). The
value is continued onto subsequent lines if those lines
have a space or tab as their first character. Field names
and values are restricted to 7-bit ASCII characters. NonASCII values may be represented using MIME encoded
words.
4.1.1

Header fields

Email header fields can be multi-line, and each line
should be at most 78 characters long and in no event
more than 998 characters long.[60] Header fields defined
by RFC 5322 can only contain US-ASCII characters;
for encoding characters in other sets, a syntax specified in RFC 2047 can be used.[61] Recently the IETF
EAI working group has defined some standards track
extensions,[62][63] replacing previous experimental extensions, to allow UTF-8 encoded Unicode characters to be
used within the header. In particular, this allows email
addresses to use non-ASCII characters. Such characters
must only be used by servers that support these extensions.
The message header must include at least the following
fields:[64]
• From: The email address, and optionally the name
of the author(s). In many email clients not changeable except through changing account settings.
• Date: The local time and date when the message was
written. Like the From: field, many email clients fill
this in automatically when sending. The recipient’s
client may then display the time in the format and
time zone local to him/her.
The message header should include at least the following
fields:[65]

• To: The email address(es), and optionally name(s)
of the message’s recipient(s). Indicates primary recipients (multiple allowed), for secondary recipients
see Cc: and Bcc: below.
• Subject: A brief summary of the topic of the message. Certain abbreviations are commonly used in
the subject, including “RE:" and “FW:".
• Bcc: Blind carbon copy; addresses added to the
SMTP delivery list but not (usually) listed in the
message data, remaining invisible to other recipients.
• Cc: Carbon copy; Many email clients will mark
email in one’s inbox differently depending on
whether they are in the To: or Cc: list.
• Content-Type: Information about how the message
is to be displayed, usually a MIME type.
• Precedence: commonly with values “bulk”, “junk”,
or “list"; used to indicate that automated “vacation”
or “out of office” responses should not be returned
for this mail, e.g. to prevent vacation notices from
being sent to all other subscribers of a mailing list.
Sendmail uses this header to affect prioritization of
queued email, with “Precedence: special-delivery”
messages delivered sooner. With modern highbandwidth networks delivery priority is less of an issue than it once was. Microsoft Exchange respects a
fine-grained automatic response suppression mechanism, the X-Auto-Response-Suppress header.[67]
• References: Message-ID of the message that this is
a reply to, and the message-id of the message the
previous reply was a reply to, etc.
• Reply-To: Address that should be used to reply to
the message.
• Sender: Address of the actual sender acting on behalf of the author listed in the From: field (secretary,
list manager, etc.).
• Archived-At: A direct link to the archived form of
an individual email message.

• Message-ID: Also an automatically generated field;
used to prevent multiple delivery and for reference
Note that the To: field is not necessarily related to the
in In-Reply-To: (see below).
addresses to which the message is delivered. The actual
• In-Reply-To: Message-ID of the message that this is delivery list is supplied separately to the transport protoa reply to. Used to link related messages together. col, SMTP, which may or may not originally have been
This field only applies for reply messages.
extracted from the header content. The “To:" field is similar to the addressing at the top of a conventional letter
RFC 3864 describes registration procedures for message which is delivered according to the address on the outer
header fields at the IANA; it provides for permanent and envelope. In the same way, the “From:" field does not

6

5 SERVERS AND CLIENT APPLICATIONS

have to be the real sender of the email message. Some
mail servers apply email authentication systems to messages being relayed. Data pertaining to server’s activity is
also part of the header, as defined below.

the user. HTML email messages often include an automatically generated plain text copy as well, for compatibility reasons.

Advantages of HTML include the ability to include inSMTP defines the trace information of a message, which line links and images, set apart previous messages in
is also saved in the header using the following two block quotes, wrap naturally on any display, use emphasis
fields:[68]
such as underlines and italics, and change font styles. Disadvantages include the increased size of the email, pri• Received: when an SMTP server accepts a message vacy concerns about web bugs, abuse of HTML email as
it inserts this trace record at the top of the header a vector for phishing attacks and the spread of malicious
software.[75]
(last to first).
• Return-Path: when the delivery SMTP server makes Some web based Mailing lists recommend that all posts
in plain-text, with 72 or 80 characters per
the final delivery of a message, it inserts this field at be made
[76][77]
line
for all the above reasons, but also because they
the top of the header.
have a significant number of readers using text-based
email clients such as Mutt.
Other header fields that are added on top of the header
by the receiving server may be called trace fields, in a Some Microsoft email clients allow rich formatting using RTF, but unless the recipient is guaranteed to have a
broader sense.[69]
compatible email client this should be avoided.[78]
• Authentication-Results: when a server carries out au- In order to ensure that HTML sent in an email is rendered
thentication checks, it can save the results in this properly by the recipient’s client software, an additional
field for consumption by downstream agents.[70]
header must be specified when sending: “Content-type:
• Received-SPF: stores results of SPF checks in more text/html”. Most email programs send this header automatically.
detail than Authentication-Results.[71]
• Auto-Submitted: is used to mark automatically generated messages.[72]

5 Servers and client applications

• VBR-Info: claims VBR whitelisting[73]

4.2
4.2.1

Message body
Content encoding

Email was originally designed for 7-bit ASCII.[74] Most
email software is 8-bit clean but must assume it will communicate with 7-bit servers and mail readers. The MIME
standard introduced character set specifiers and two content transfer encodings to enable transmission of nonASCII data: quoted printable for mostly 7 bit content with
a few characters outside that range and base64 for arbitrary binary data. The 8BITMIME and BINARY extensions were introduced to allow transmission of mail without the need for these encodings, but many mail transport
agents still do not support them fully. In some countries,
several encoding schemes coexist; as the result, by default, the message in a non-Latin alphabet language appears in non-readable form (the only exception is coincidence, when the sender and receiver use the same encoding scheme). Therefore, for international character sets,
Unicode is growing in popularity.

The interface of an email client, Thunderbird.

Messages are exchanged between hosts using the Simple
Mail Transfer Protocol with software programs called
mail transfer agents (MTAs); and delivered to a mail store
by programs called mail delivery agents (MDAs, also
sometimes called local delivery agents, LDAs). Users
can retrieve their messages from servers using standard
protocols such as POP or IMAP, or, as is more likely in a
large corporate environment, with a proprietary protocol
specific to Novell Groupwise, Lotus Notes or Microsoft
Exchange Servers. Webmail interfaces allow users to ac4.2.2 Plain text and HTML
cess their mail with any standard web browser, from any
Most modern graphic email clients allow the use of either computer, rather than relying on an email client. Proplain text or HTML for the message body at the option of grams used by users for retrieving, reading, and managing

7
email are called mail user agents (MUAs).
Mail can be stored on the client, on the server side, or
in both places. Standard formats for mailboxes include
Maildir and mbox. Several prominent email clients use
their own proprietary format and require conversion software to transfer email between them. Server-side storage is often in a proprietary format but since access is
through a standard protocol such as IMAP, moving email
from one server to another can be done with any MUA
supporting the protocol.

The URI scheme, as registered with the IANA, defines
the mailto: scheme for SMTP email addresses. Though
its use is not strictly defined, URLs of this form are intended to be used to open the new message window of
the user’s mail client when the URL is activated, with the
address as defined by the URL in the To: field.[80]

6 Types

Accepting a message obliges an MTA to deliver it,[79] and 6.1 Web-based email (webmail)
when a message cannot be delivered, that MTA must send
a bounce message back to the sender, indicating the prob- Main article: Webmail
lem.
Many email providers have a web-based email client (e.g.
AOL Mail, Gmail, Outlook.com and Yahoo! Mail). This
5.1 Filename extensions
allows users to log into the email account by using any
compatible web browser to send and receive their email.
Upon reception of email messages, email client applicaMail is typically not downloaded to the client, so can't be
tions save messages in operating system files in the file
read without a current Internet connection.
system. Some clients save individual messages as separate files, while others use various database formats, often
proprietary, for collective storage. A historical standard 6.2 POP3 email services
of storage is the mbox format. The specific format used
is often indicated by special filename extensions:
Main article: POP3
eml Used by many email clients including Novell GroupWise, Microsoft Outlook Express, Lotus notes,
Windows Mail, Mozilla Thunderbird, and Postbox.
The files are plain text in MIME format, containing
the email header as well as the message contents and
attachments in one or more of several formats.
emlx Used by Apple Mail.
msg Used by Microsoft Office Outlook and OfficeLogic
Groupware.
mbx Used by Opera Mail, KMail, and Apple Mail based
on the mbox format.
Some applications (like Apple Mail) leave attachments
encoded in messages for searching while also saving separate copies of the attachments. Others separate attachments from messages and save them in a specific directory.

POP3 is the acronym for Post Office Protocol 3. In a
POP3 email account, email messages are downloaded
to the client device (i.e. a computer) and then they are
deleted from the mail server unless specific instruction
to save has been given . It is difficult to save and view
messages on multiple devices. Also, the messages sent
from the computer/one device are not copied to the Sent
Items folder on the (other) devices. The messages are
deleted from the server to make room for more incoming
messages. POP supports simple download-and-delete requirements for access to remote mailboxes (termed maildrop in the POP RFC’s).[81] Although most POP clients
have an option to leave messages on the server after
downloading a copy of them, most email clients using
POP3 simply connect, retrieve all messages, store them
on the client device as new messages, delete them from
the server, and then disconnect.

6.3 IMAP email servers

Mobile devices, such as cell phones and tablet computers, commonly have the ability to receive email. Since Main article: IMAP
users may always have their mobile device with them,
users may access email significantly faster on these devices than through other methods, such as desktop com- IMAP refers to Internet Message Access Protocol. With
an IMAP account, a user’s account has access to mail
puters or laptops.
folders on the mail server and can use any compatible
device to read and reply to messages, as long as such
a device can access the server. Small portable devices
5.2 URI scheme mailto
like smartphones are increasingly used to check email
Main article: mailto
while travelling, and to make brief replies, larger devices
with better keyboard access being used to reply at greater

8

7

USE

length. IMAP shows the headers of messages, the sender load mail when offline, it also allows the small business
and the subject and the device needs to request to down- user to have multiple users’ email IDs with just one email
load specific messages. Usually mail is left in folders in connection.
the mail server.
7.3.1 Pros

6.4

MAPI email servers

Main article: MAPI
Messaging Application Programming Interface (MAPI)
is a messaging architecture and a Component Object
Model based API for Microsoft Windows.

7
7.1

Use
Flaming

Flaming occurs when a person sends a message with angry or antagonistic content. The term is derived from
the use of the word Incendiary to describe particularly
heated email discussions. Flaming is assumed to be more
common today because of the ease and impersonality of
email communications: confrontations in person or via
telephone require direct interaction, where social norms
encourage civility, whereas typing a message to another
person is an indirect interaction, so civility may be forgotten.

7.2

Email bankruptcy

Main article: Email bankruptcy

• The problem of logistics: Much of the business world
relies on communications between people who are
not physically in the same building, area, or even
country; setting up and attending an in-person meeting, telephone call, or conference call can be inconvenient, time-consuming, and costly. Email provides a method of exchanging information between
two or more people with no set-up costs and that is
generally far less expensive than a physical meeting
or phone call.
• The problem of synchronisation: With real time
communication by meetings or phone calls, participants must work on the same schedule, and each participant must spend the same amount of time in the
meeting or call. Email allows asynchrony: each participant may control their schedule independently.
7.3.2 Cons
Most business workers today spend from one to two hours
of their working day using email: reading, ordering,
sorting, 're-contextualizing' fragmented information, and
writing email.[83] The use of email is increasing worldwide:
• Information overload: Email is a push technology
– the sender controls who receives the information.
Convenient availability of mailing lists and use of
“copy all” can lead to people receiving unwanted or
irrelevant information of no use to them.

Also known as “email fatigue”, email bankruptcy is when
a user ignores a large number of email messages after
falling behind in reading and answering them. The reason for falling behind is often due to information overload
• Inconsistency: Email can duplicate information.
and a general sense there is so much information that it is
This can be a problem when a large team is working
not possible to read it all. As a solution, people occasionon documents and information while not in constant
ally send a boilerplate message explaining that the email
contact with the other members of their team.
inbox is being cleared out. Harvard University law professor Lawrence Lessig is credited with coining this term,
Despite these disadvantages, email has become the most
but he may only have popularized it.[82]
widely used medium of communication within the business world. A 2010 study on workplace communication by Paytronics found 83% of U.S. knowledge workers
7.3 In business
felt email was critical to their success and productivity at
[84]
Email was widely accepted by the business community as work.
the first broad electronic communication medium and was
the first 'e-revolution' in business communication. Email 7.3.3 Research on email marketing
is very simple to understand and like postal mail, email
solves two basic problems of communication: logistics Marketing research suggests that opt-in email marketing
and synchronization (see below).
can be viewed as useful by consumers if it contains inLAN based email is also an emerging form of usage for formation such as special sales offerings and new product
business. It not only allows the business user to down- information. Offering interesting hyperlinks or generic

9
information on consumer trends is less useful.[85] This re• Denial of Service [88]
search by Martin et al. (2003) also shows that if consumers find email marketing useful, they are likely to visit There are also concerns regarding the email privacy.
a store, thereby overcoming limitations of Internet marketing such as not being able to touch or try on a product.

9 Problems
7.4

Mobile

Email has become widely used on smart phones. Mobile apps for email increase accessibility to the medium.
While before users could only access email on computers, it is now possible for users to check their email out
of the home and out of the library while on the go. Alerts
can also be sent to the phone to notify them immediately of new messages. This has given email the ability to
be used for more frequent communication between users
and allowed them to check their email and write messages
throughout the day.

9.1 Attachment size limitation
Main article: Email attachment

Email messages may have one or more attachments, i.e.
MIME parts intended to provide copies of files. Attachments serve the purpose of delivering binary or text files
of unspecified size. In principle there is no technical intrinsic restriction in the InternetMessage Format, SMTP
protocol or MIME limiting the size or number of attachments. In practice, however, email service providers imIt was found that US adults check their email more plement various limitations on the permissible size of files
than they browse the web or check their Facebook ac- or the size of an entire message.
counts, making email the most popular activity for users
often a small atto do on their smart phones. 78% of the respondents in Furthermore, due to technical reasons, [89]
tachment
can
increase
in
size
when
sent,
which can be
the study revealed that they check their email on their
confusing
to
senders
when
trying
to
assess
whether
they
phone.[86] It was also found that 30% of consumers use
can
or
cannot
send
a
file
by
email,
and
this
can
result
in
only their smartphone to check their email, and 91% were
their
message
being
rejected.
likely to check their email at least once per day on their
smartphone. However, the percentage of consumers us- As larger and larger file sizes are being created and traded,
ing email on smartphone ranges and differs dramatically many users are either forced to upload and download their
across different countries. For example, in comparison files using an FTP server, or more popularly, use online
to 75% of those consumers in the US who used it, only file sharing facilities or services, usually over web-friendly
17% in India did.[87]
HTTP, in order to send and receive them.

8

Security

Data confidentiality, authentication, integrity, nonrepudiation, access control, and availability are the most
important security services that should be considered in
secure applications and systems, but they are not provided in traditional email protocols. Email is vulnerable
to both passive and active attacks. Passive threats include
release of message contents, and traffic analysis while
active threats include modification of message contents,
masquerade, replay, and denial-of-service (DoS). All the
mentioned threats are applicable to the traditional email
protocols:
• Disclosure of Information
• Traffic analysis
• Modification of messages
• Masquerade
• Replay of previous messages
• Spoofing

9.2 Information overload
A December 2007 New York Times blog post described
information overload as “a $650 Billion Drag on the
Economy”,[90] and the New York Times reported in
April 2008 that “E-MAIL has become the bane of some
people’s professional lives” due to information overload,
yet “none of the current wave of high-profile Internet
start-ups focused on email really eliminates the problem of email overload because none helps us prepare
replies”.[91] GigaOm posted a similar article in September 2010, highlighting research that found 57% of knowledge workers were overwhelmed by the volume of email
they received.[84] Technology investors reflect similar
concerns.[92]
In October 2010, CNN published an article titled “Happy
Information Overload Day” that compiled research about
email overload from IT companies and productivity experts. According to Basex, the average knowledge worker
receives 93 messages per day. Subsequent studies have
reported higher numbers.[93] Marsha Egan, an email productivity expert, called email technology both a blessing
and a curse in the article. She stated, “Everyone just
learns that they have to have it dinging and flashing and

10

9 PROBLEMS

open just in case the boss e-mails,” she said. “The best 9.6 Privacy concerns
gift any group can give each other is to never use e-mail
urgently. If you need it within three hours, pick up the Main article: Internet privacy
phone.”[94]

9.3

Spamming and computer viruses

The usefulness of email is being threatened by four phenomena: email bombardment, spamming, phishing, and
email worms.

Today it can be important to distinguish between Internet and internal email systems. Internet email may travel
and be stored on networks and computers without the
sender’s or the recipient’s control. During the transit time
it is possible that third parties read or even modify the
content. Internal mail systems, in which the information
never leaves the organizational network, may be more secure, although information technology personnel and others whose function may involve monitoring or managing
may be accessing the email of other employees.

Spamming is unsolicited commercial (or bulk) email. Because of the minuscule cost of sending email, spammers
can send hundreds of millions of email messages each
day over an inexpensive Internet connection. Hundreds Email privacy, without some security precautions, can be
of active spammers sending this volume of mail results compromised because:
in information overload for many computer users who re• email messages are generally not encrypted.
ceive voluminous unsolicited email each day.[95][96]
Email worms use email as a way of replicating themselves
into vulnerable computers. Although the first email worm
affected UNIX computers, the problem is most common
today on the Microsoft Windows operating system.

• email messages have to go through intermediate
computers before reaching their destination, meaning it is relatively easy for others to intercept and
read messages.

The combination of spam and worm programs results in
users receiving a constant drizzle of junk email, which
reduces the usefulness of email as a practical tool.

• many Internet Service Providers (ISP) store copies
of email messages on their mail servers before they
are delivered. The backups of these can remain for
up to several months on their server, despite deletion
from the mailbox.

A number of anti-spam techniques mitigate the impact
of spam. In the United States, U.S. Congress has also
passed a law, the Can Spam Act of 2003, attempting to
• the “Received:"-fields and other information in the
regulate such email. Australia also has very strict spam
email can often identify the sender, preventing
laws restricting the sending of spam from an Australian
anonymous communication.
ISP,[97] but its impact has been minimal since most spam
comes from regimes that seem reluctant to regulate the
There are cryptography applications that can serve as
sending of spam.
a remedy to one or more of the above. For example,
Virtual Private Networks or the Tor anonymity network
can be used to encrypt traffic from the user machine
9.4 Email spoofing
to a safer network while GPG, PGP, SMEmail,[98] or
S/MIME can be used for end-to-end message encryption, and SMTP STARTTLS or SMTP over Transport
Main article: Email spoofing
Layer Security/Secure Sockets Layer can be used to encrypt communications for a single mail hop between the
Email spoofing occurs when the email message header
SMTP client and the SMTP server.
is designed to make the message appear to come from a
known or trusted source. Email spam and phishing meth- Additionally, many mail user agents do not protect logins
ods typically use spoofing to mislead the recipient about and passwords, making them easy to intercept by an attacker. Encrypted authentication schemes such as SASL
the true message origin.
prevent this.

9.5

Email bombing

Finally, attached files share many of the same hazards
as those found in peer-to-peer filesharing. Attached files
may contain trojans or viruses.

Main article: Email bomb

9.7 Tracking of sent mail
Email bombing is the intentional sending of large volumes
of messages to a target address. The overloading of the The original SMTP mail service provides limited mechtarget email address can render it unusable and can even anisms for tracking a transmitted message, and none for
verifying that it has been delivered or read. It requires
cause the mail server to crash.

11
that each mail server must either deliver it onward or return a failure notice (bounce message), but both software
bugs and system failures can cause messages to be lost. To
remedy this, the IETF introduced Delivery Status Notifications (delivery receipts) and Message Disposition Notifications (return receipts); however, these are not universally deployed in production. (A complete Message
Tracking mechanism was also defined, but it never gained
traction; see RFCs 3885[99] through 3888.[100] )
Many ISPs now deliberately disable non-delivery reports
(NDRs) and delivery receipts due to the activities of
spammers:
• Delivery Reports can be used to verify whether an
address exists and so is available to be spammed
• If the spammer uses a forged sender email address
(email spoofing), then the innocent email address
that was used can be flooded with NDRs from the
many invalid email addresses the spammer may have
attempted to mail. These NDRs then constitute
spam from the ISP to the innocent user
In the absence of standard methods, a range of system
based around the use of web bugs have been developed.
However, these are often seen as underhand or raising privacy concerns,[101][102][103] and only work with email clients that support rendering of HTML. Many mail
clients now default to not showing “web content”.[104]
Webmail providors can also disrupt web bugs by precaching images.[105]

10

U.S. government

The U.S. state and federal governments have been involved in electronic messaging and the development of
email in several different ways.
Starting in 1977, the U.S. Postal Service (USPS) recognized that electronic messaging and electronic transactions posed a significant threat to First Class mail volumes
and revenue. The USPS explored an electronic messaging initiative in 1977 and later disbanded it. Twenty
years later, in 1997, when email volume overtook postal
mail volume, the USPS was again urged to embrace
email, and the USPS declined to provide email as a
service.[106][107][108] The USPS initiated an experimental email service known as E-COM. E-COM provided
a method for the simple exchange of text messages. In
2011, shortly after the USPS reported its state of financial
bankruptcy, the USPS Office of Inspector General (OIG)
began exploring the possibilities of generating revenue
through email servicing.[109][110][111] Electronic messages
were transmitted to a post office, printed out, and delivered as hard copy. To take advantage of the service, an
individual had to transmit at least 200 messages. The delivery time of the messages was the same as First Class

mail and cost 26 cents. Both the Postal Regulatory Commission and the Federal Communications Commission
opposed E-COM. The FCC concluded that E-COM constituted common carriage under its jurisdiction and the
USPS would have to file a tariff.[112] Three years after
initiating the service, USPS canceled E-COM and attempted to sell it off.[113][114][115][116][117][118]
The early ARPANET dealt with multiple email clients
that had various, and at times incompatible, formats. For
example, in the Multics, the "@" sign meant “kill line”
and anything before the "@" sign was ignored, so Multics users had to use a command-line option to specify
the destination system.[28] The Department of Defense
DARPA desired to have uniformity and interoperability for email and therefore funded efforts to drive towards unified inter-operable standards. This led to David
Crocker, John Vittal, Kenneth Pogran, and Austin Henderson publishing RFC 733, “Standard for the Format of
ARPA Network Text Message” (November 21, 1977), a
subset of which provided a stable base for common use on
the ARPANET, but which was not fully effective, and in
1979, a meeting was held at BBN to resolve incompatibility issues. Jon Postel recounted the meeting in RFC 808,
“Summary of Computer Mail Services Meeting Held at
BBN on 10 January 1979” (March 1, 1982), which includes an appendix listing the varying email systems at the
time. This, in turn, lead to the release of David Crocker’s
RFC 822, “Standard for the Format of ARPA Internet
Text Messages” (August 13, 1982).[119] RFC 822 is a
small adaptation of RFC 733's details, notably enhancing
the host portion, to use Domain Names, that were being
developed at the same time.
The National Science Foundation took over operations of
the ARPANET and Internet from the Department of Defense, and initiated NSFNet, a new backbone for the network. A part of the NSFNet AUP forbade commercial
traffic.[120] In 1988, Vint Cerf arranged for an interconnection of MCI Mail with NSFNET on an experimental
basis. The following year Compuserve email interconnected with NSFNET. Within a few years the commercial traffic restriction was removed from NSFNETs AUP,
and NSFNET was privatised.
In the late 1990s, the Federal Trade Commission grew
concerned with fraud transpiring in email, and initiated a
series of procedures on spam, fraud, and phishing.[121] In
2004, FTC jurisdiction over spam was codified into law in
the form of the CAN SPAM Act.[122] Several other U.S.
federal agencies have also exercised jurisdiction including
the Department of Justice and the Secret Service.
NASA has provided email capabilities to astronauts
aboard the Space Shuttle and International Space Station
since 1991 when a Macintosh Portable was used aboard
Space Shuttle mission STS-43 to send the first email via
AppleLink.[123][124][125] Today astronauts aboard the International Space Station have email capabilities via the
wireless networking throughout the station and are con-

12

12

nected to the ground at 10 Mbit/s Earth to station and 3
Mbit/s station to Earth, comparable to home DSL connection speeds.[126]

REFERENCES

• Mailing list archive
• Telegraphy
• Lexigram

11

See also

• Email encryption
• HTML email
• Internet fax
• Privacy-enhanced Electronic Mail
• Dark Mail Alliance
• Push email
• X-Originating-IP
• Anti-spam techniques
• E-card
• Email art
• Email storm
• List of email subject abbreviations
• Information overload
• Netiquette
• Posting style
• Usenet quoting
• Biff
• Email authentication
• Comparison of email clients
• Email hosting service
• Internet mail standards
• RSS to email
• Unicode and email
• Webmail, Comparison of webmail providers
• Anonymous remailer
• Disposable email address
• Email digest
• Email encryption

• MCI Mail
• X400

12 References
[1] “RFC 5321 – Simple Mail Transfer Protocol”. Network
Working Group. Retrieved 19 January 2015.
[2] Google Ngram Viewer. Books.google.com. Retrieved
2013-04-21.
[3] Ron Brown, Fax invades the mail market, New Scientist,
Vol. 56, No. 817 (Oct., 26, 1972), pages 218–221.
[4] Herbert P. Luckett, What’s News: Electronic-mail delivery gets started, Popular Science, Vol. 202, No. 3 (March
1973); page 85
[5] (Partridge 2008)
[6] http://dir.yahoo.com/business_and_economy/business_
to_business/communications_and_networking/internet_
and_world_wide_web/email_providers/free_email/
[7] ""Email” or “e-mail"". English Language & Usage – Stack
Exchange. August 25, 2010. Retrieved September 26,
2010.
[8] “RFC Editor Terms List”. IETF. This is suggested by the
RFC Document Style Guide
[9] “Yahoo style guide”. Styleguide.yahoo.com. Retrieved
2014-01-09.
[10] AP Stylebook editors share big changes from the
American Copy Editors Society
[11] Gerri Berendzen; Daniel Hunt. “AP changes e-mail to
email”. 15th National Conference of the American Copy
Editors Society (2011, Phoenix). ACES. Retrieved 23
March 2011.
[12] AskOxford Language Query team. “What is the correct
way to spell 'e' words such as 'email', 'ecommerce', 'egovernment'?". FAQ. Oxford University Press. Archived
from the original on July 1, 2008. Retrieved 4 September 2009. We recommend email, as this is now by far the
most common form
[13] “Reference.com”. Dictionary.reference.com. Retrieved
2014-01-09.
[14] Random House Unabridged Dictionary, 2006

• Email tracking

[15] The American Heritage Dictionary of the English Language, Fourth Edition

• Electronic mailing list

[16] Princeton University WordNet 3.0

• Mailer-Daemon

[17] The American Heritage Science Dictionary, 2002

13

[18] “Merriam-Webster Dictionary”. Merriam-Webster. Retrieved 9 May 2014.
[19] “RFC 821 (rfc821) – Simple Mail Transfer Protocol”.
Faqs.org. 1971-06-11. Retrieved 2014-01-09.
[20] “RFC 1939 (rfc1939) – Post Office Protocol – Version 3”.
Faqs.org. Retrieved 2014-01-09.
[21] “RFC 3501 (rfc3501) – Internet Message Access Protocol
– version 4rev1”. Faqs.org. Retrieved 2014-01-09.
[22] "''"RFC Style Guide"'', Table of decisions on consistent
usage in RFC”. Retrieved 2014-01-09.
[23] “Excerpt from the FAQ list of the Usenet newsgroup
alt.usage.english”. Alt-usage-english.org. Retrieved
2014-01-09.
[24] USPS Support Panel, Louis T Rader, Chair, Chapter
IV: Systems, Electronic Message Systems for the U.S.
Postal Service, National Academy of Sciences, Washington, D.C., 1976; pages 27–35.
[25] “CTSS, Compatible Time-Sharing System” (September
4, 2006), University of South Alabama, USA-CTSS.
[26] an IBM 7094
[27] Tom Van Vleck, “The IBM 7094 and CTSS” (September 10, 2004), Multicians.org (Multics), web: Multicians7094.
[28] Tom Van Vleck. “The History of Electronic Mail”.
[29] IBM, 1440/1460 Administrative Terminal System (1440CX-07X and 1460-CX-08X) Application Description
(PDF), Second Edition, IBM, p. 10, H20-0129-1
[30] IBM, System/36O Administrative Terminal System DOS
(ATS/DOS) Program Description Manual, IBM, H200508
[31] IBM, System/360 Administrative Terminal System-OS
(ATS/OS) Application Description Manual, IBM, H200297
[32] Ray Tomlinson. “The First Network Email”. Openmap.bbn.com. Retrieved 2014-01-09.
[33] “Version 3 Unix mail(1) manual page from 10/25/1972”.
Minnie.tuhs.org. Retrieved 2014-01-09.
[34] “Version 6 Unix mail(1) manual page from 2/21/1975”.
Minnie.tuhs.org. Retrieved 2014-01-09.
[35] APL Quotations and Anecdotes, including Leslie Goldsmith's story of the Mailbox

[40] Stromberg, Joseph (22 February 2012). “A Piece of
Email History Comes to the American History Museum”.
Smithsonian Institution. Retrieved 11 June 2012.
[41] “Statement from the National Museum of American History: Collection of Materials from V.A. Shiva Ayyadurai”
(Press release). National Museum of American History.
23 February 2012. Retrieved 19 February 2013.
[42] A Mail Handling System, Bruce Borden, The Rand Corporation, 1979.
[43] "...PROFS changed the way organizations communicated,
collaborated and approached work when it was introduced
by IBM’s Data Processing Division in 1981...”, IBM.com
[44] “1982 – The National Security Council (NSC) staff at
the White House acquires a prototype electronic mail system, from IBM, called the Professional Office System
(PROFs)....”, fas.org
[45] “Gordon Bell’s timeline of Digital Equipment Corporation”. Research.microsoft.com. 1998-01-30. Retrieved
2014-01-09.
[46] with various vendors supplying gateway software to link
these incompatible systems
[47] Ray Tomlinson. “The First Network Email”.
[48] “Version 7 Unix manual: “UUCP Implementation Description” by D. A. Nowitz, and “A Dial-Up Network of
UNIX Systems” by D. A. Nowitz and M. E. Lesk”. Retrieved 2014-01-09.
[49] Setting up the Fourth Berkeley Software Tape, William N.
Joy, Ozalp Babaoglu, Keith Sklower, University of California, Berkeley, 1980.
[50] Mail(1), UNIX Programmer’s Manual, 4BSD, University
of California, Berkeley, 1980.
[51] “BITNET History”, livinginternet.com
[52] “Delivering the Enterprise Message, 19 Sep 1994, Daniel
Blum, Network World
[53] "...offers improved performance, greater reliability and
much more flexibility in everything from communications
hardware to scheduling...”, 03/07/94, Mark Gibbs, Network World
[54] “MHS: Correct Addressing format to DaVinci Email via
MHS”. Microsoft Support Knowledge Base. Retrieved
2007-01-15.

[36] History of the Internet, including Carter/Mondale use of
email

[55] “Email History”. Livinginternet.com. 1996-05-13. Retrieved 2014-01-09.

[37] David Wooley, PLATO: The Emergence of an Online
Community, 1994.

[56] “The Technical Development of Internet Email” Craig
Partridge, April–June 2008, p.5

[38] The Mail Reference Manual, Kurt Shoens, University of
California, Berkeley, 1979.

[57] Wave New World,Time Magazine, October 19, 2009,
p.48

[39] An Introduction to the Berkeley Network, Eric Schmidt,
University of California, Berkeley, 1979.

[58] How E-mail Works (internet video). howstuffworks.com.
2008.

14

12

REFERENCES

[59] Simpson, Ken (October 3, 2008). “An update to the email
standards”. MailChannels Blog Entry.

[81] Allen, David (2004). Windows to Linux. Prentice Hall. p.
192.

[60] P. Resnick, Ed. (October 2008). “RFC 5322, Internet
Message Format”. IETF.

[82] Barrett, Grant (December 23, 2007). “All We Are Saying.”. New York Times. Retrieved 2007-12-24.

[61] Moore, K (November 1996). “MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII Text”. IETF. Retrieved 2012-0121.

[83] “Email Right to Privacy – Why Small Businesses Care”.
Anita Campbell. 2007-06-19.

[62] A Yang, Ed. (February 2012). “RFC 6532, Internationalized Email Headers”. IETF. ISSN 2070-1721.
[63] J. Yao, Ed., W. Mao, Ed. (February 2012). “RFC 6531,
SMTP Extension for Internationalized Email Addresses”.
IETF. ISSN 2070-1721.
[64] “RFC 5322, 3.6. Field Definitions”. Tools.ietf.org. October 2008. Retrieved 2014-01-09.
[65] “RFC 5322, 3.6.4. Identification Fields”. Tools.ietf.org.
October 2008. Retrieved 2014-01-09.
[66] “RFC 5064”. Tools.ietf.org. December 2007. Retrieved
2014-01-09.
[67] Microsoft, Auto Response Suppress, 2010, microsoft reference, 2010 Sep 22
[68] John Klensin (October 2008). “Trace Information”.
Simple Mail Transfer Protocol. IETF. sec. 4.4. RFC
5321. https://tools.ietf.org/html/rfc5321#section-4.4.
[69] John Levine (14 January 2012). “Trace headers”. email
message. IETF. Retrieved 16 January 2012. there are
many more trace headers than those two
[70] This extensible field is defined by RFC 7001, that also defines an IANA registry of Email Authentication Parameters.
[71] RFC 7208.

[84] By Om Malik, GigaOm. "Is Email a Curse or a Boon?"
September 22, 2010. Retrieved October 11, 2010.
[85] Martin, Brett A. S., Joel Van Durme, Mika Raulas, and
Marko Merisavo (2003), “E-mail Marketing: Exploratory
Insights from Finland”, Journal of Advertising Research,
43 (3), 293–300.
[86] Matt McGee. March 28, 2013. Email Is Top Activity On Smartphones, Ahead Of Web Browsing
& Facebook [Study].
http://marketingland.com/
smartphone-activities-study-email-web-facebook-37954
[87] Jordan van Rijn. April 2014. The ultimate mobile
email statistics overview. http://www.emailmonday.com/
mobile-email-usage-statistics
[88] SMEmail – A New Protocol for the Secure E-mail in
Mobile Environments, Proceedings of the Australian
Telecommunications Networks and Applications Conference (ATNAC'08), pp. 39–44, Adelaide, Australia, Dec.
2008.
[89] “Exchange 2007: Attachment Size Increase,...”. TechNet
Magazine, Microsoft.com US. 2010-03-25.
[90] Lohr, Steve (2007-12-20). “Is Information Overload a
$650 Billion Drag on the Economy?". New York Times.
Retrieved May 1, 2010.
[91] Stross, Randall (2008-04-20). “Struggling to Evade the
E-Mail Tsunami”. New York Times. Retrieved May 1,
2010.

[72] Defined in RFC 3834, and updated by RFC 5436.
[73] RFC 5518.

[92] “Did Darwin Skip Over Email?". Foundry Group. 200804-28.

[74] Craig Hunt (2002). TCP/IP Network Administration.
O'Reilly Media. p. 70. ISBN 978-0-596-00297-8.

[93] Radicati, Sara. “Email Statistics Report, 2010” (PDF).

[75] “Email policies that prevent viruses”.

[94] Gross, Doug (July 26, 2011). “Happy Information Overload Day!". CNN.

[76] “When posting to a RootsWeb mailing list...”.
Helpdesk.rootsweb.com. Retrieved 2014-01-09.
[77] "...Plain text, 72 characters per line...”. Openbsd.org. Retrieved 2014-01-09.
[78] “How to Prevent the Winmail.dat File from Being Sent
to Internet Users”. Support.microsoft.com. 2010-07-02.
Retrieved 2014-01-09.
[79] In practice, some accepted messages may nowadays not be
delivered to the recipient’s InBox, but instead to a Spam or
Junk folder which, especially in a corporate environment,
may be inaccessible to the recipient

[95] Rich Kawanagh. The top ten email spam list of 2005.
ITVibe news, 2006, January 02, ITvibe.com
[96] How Microsoft is losing the war on spam Salon.com
[97] Spam Bill 2003 (PDF)
[98] SMEmail – A New Protocol for the Secure E-mail in
Mobile Environments, Proceedings of the Australian
Telecommunications Networks and Applications Conference (ATNAC'08), pp. 39–44, Adelaide, Australia, Dec.
2008.

[99] RFC 3885, SMTP Service Extension for Message Tracking
[80] RFC 2368 section 3 : by Paul Hoffman in 1998 discusses
operation of the “mailto” URL.
[100] RFC 3888, Message Tracking Model and Requirements

15

[101] Amy Harmon (2000-11-22). “Software That Tracks E- [123] Cowing, Keith (2000-09-18). “2001: A Space Laptop |
Mail Is Raising Privacy Concerns”. The New York Times.
SpaceRef – Your Space Reference”. Spaceref.com. ReRetrieved 2012-01-13.
trieved 2014-01-09.
[102] “About.com”. Email.about.com. 2013-12-19. Retrieved
[124] “The Mac Observer – This Week in Apple History – Au2014-01-09.
gust 22–31: “Welcome, IBM. Seriously,” Too Late to License”. Macobserver.com. 2004-10-31. Retrieved 2014[103] “Webdevelopersnotes.com”. Webdevelopersnotes.com.
01-09.
Retrieved 2014-01-09.
[104] “Outlook: Web Bugs & Blocked HTML Images”, slip- [125] Linzmayer, Owen W. (2004). Apple confidential 2.0 :
stick.com
the definitive history of the world’s most colorful company
([Rev. 2. ed.]. ed.). San Francisco, Calif.: No Starch
[105] “Gmail blows up e-mail marketing...”, Ron Amadeo, Dec
Press. ISBN 1-59327-010-0.
13 2013, Ars Technica
[106] http://www.fastcompany.com/1780716/
can-technology-save-us-postal-service

[126] Bilton, Nick (January 22, 2010).
Space”. New York Times.

“First Tweet from

[107] http://tech.mit.edu/V131/N60/emaillab.html
[108] http://www.fedtechmagazine.com/article/2013/01/
why-united-states-postal-service-taking-cues-silicon-valley

13 Further reading

[109] http://cmsw.mit.edu/usps-can-save-itself/

• Cemil Betanov, Introduction to X.400, Artech
House, ISBN 0-89006-597-7.

[110] http://bostinno.streetwise.co/2012/01/13/
could-email-save-snail-mail-or-is-the-internet-too-reliant-on-the-usps/
[111] http://www.bostonglobe.com/lifestyle/2012/03/02/
dear-usps/V4GJ8w9UCcfV4v0WiVjvmK/story.html
[112] In re Request for declaratory ruling and investigation by
Graphnet Systems, Inc., concerning the proposed E-COM
service, FCC Docket No. 79-6 (September 4, 1979)
[113] History of the United States Postal Service, USPS, 13
November 2014
[114] Hardy, Ian R; The Evolution of ARPANET Email; 199605-13; History Thesis Paper; University of California at
Berkeley
[115] James Bovard, The Law Dinosaur: The US Postal Service,
CATO Policy Analysis (February 1985)
[116] “Jay Akkad, The History of Email”. Cs.ucsb.edu. Retrieved 2014-01-09.

• Marsha Egan, "Inbox Detox and The Habit of
Email Excellence", Acanthus Publishing ISBN 9780-9815589-8-1
• Lawrence Hughes, Internet e-mail Protocols, Standards and Implementation, Artech House Publishers, ISBN 0-89006-939-5.
• Kevin Johnson, Internet Email Protocols: A Developer’s Guide, Addison-Wesley Professional, ISBN
0-201-43288-9.
• Pete Loshin, Essential Email Standards: RFCs and
Protocols Made Practical, John Wiley & Sons, ISBN
0-471-34597-0.

[117] “US Postal Service: Postal Activities and Laws Related to
Electronic Commerce, GAO-00-188” (PDF). Retrieved
2014-01-09.

• Partridge, Craig (April–June 2008). “The Technical Development of Internet Email” (PDF). IEEE
Annals of the History of Computing (Berlin: IEEE
Computer Society) 30 (2). ISSN 1934-1547

[118] “Implications of Electronic Mail and Message Systems
for the U.S. Postal Service , Office of Technology Assessment, Congress of the United States, August 1982”
(PDF). Retrieved 2014-01-09.

• Sara Radicati, Electronic Mail: An Introduction to the
X.400 Message Handling Standards, Mcgraw-Hill,
ISBN 0-07-051104-7.

[119] “Email History, How Email was Invented, Living Internet”. Livinginternet.com. 1996-05-13. Retrieved 201401-09.

• John Rhoton, Programmer’s Guide to Internet Mail:
SMTP, POP, IMAP, and LDAP, Elsevier, ISBN 155558-212-5.

[120] Robert Cannon. “Internet History”. Cybertelecom. Retrieved 2014-01-09.
[121] Cybertelecom : SPAM Reference
[122] Robert Cannon. “Can Spam Act”. Cybertelecom. Retrieved 2014-01-09.

• John Rhoton, X.400 and SMTP: Battle of the E-mail
Protocols, Elsevier, ISBN 1-55558-165-X.
• David Wood, Programming Internet Mail, O'Reilly,
ISBN 1-56592-479-7.

16

14

14

External links

• E-mail at DMOZ
• IANA’s list of standard header fields
• The History of Email is Dave Crocker’s attempt at
capturing the sequence of 'significant' occurrences
in the evolution of email; a collaborative effort that
also cites this page.
• The History of Electronic Mail is a personal memoir
by the implementer of an early email system
• A Look at the Origins of Network Email is a short,
yet vivid recap of the key historical facts

EXTERNAL LINKS

17

15
15.1

Text and image sources, contributors, and licenses
Text

• Email Source: http://en.wikipedia.org/wiki/Email?oldid=664283156 Contributors: Magnus Manske, The Epopt, Derek Ross, LC~enwiki,
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18

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TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES

Your Car, Mrlee321, Vituzzu, C'est moi, Anchor Link Bot, Dhoom4, Maralia, Yuva raju raj, Denisarona, Joel Rennie, Heinzi.at, Hoplon,
WikipedianMarlith, Twinsday, ClueBot, Agent2693, WilliamRoper, Mhackmer, PipepBot, MWelchUK, The Thing That Should Not Be,
Unbuttered Parsnip, Joeldbenson, Arakunem, Startvtk, Meekywiki, VQuakr, Mild Bill Hiccup, TheOldJacobite, Lisabelleg, Niceguyedc,
सुभाष राऊत, Nebula17, Pat80, HMBot~enwiki, Melizg, DragonBot, Gnome de plume, Jusdafax, Sean 1996, Smtc123, Leonard^Bloom,
Dr.s.t.ruggling, Muhandes, KnowledgeBased, Lartoven, Sun Creator, Crackerwashere, Thuja, Asdasd12324, Jotterbot, Cmartell, El pobre
Pedro, Razorflame, Durcar86, Galaxy250, Inspector 34, Bald Zebra, Armando49, Thingg, Callmejosh, Aitias, 7, Sd324, Eliezer Aharon,
Crazyperson324, PCHS-NJROTC, Canihaveacookie, Johnuniq, SoxBot III, Goodvac, Pivotrock, DumZiBoT, Lunboks, Raphel M. Markez,
XLinkBot, Prof Wrong, Will-B, Emmy.rose, Pichpich, Pgallert, Avoided, Sogle, Skarebo, WikHead, SilvonenBot, Mifter, Frood, Alexius08, Mm40, Mozillar, Param0r33, HexaChord, Merry Devil, Mogglewump, Prowikipedians, Addbot, Xp54321, Grayfell, Willking1979,
Some jerk on the Internet, Jafeluv, Mabdul, Aspandphp, EjsBot, Iceblock, PatrickFlaherty, Boomur, CellMan0677, Fieldday-sunday, Karcamp, Bnorrie, Ilya-108, Fluffernutter, Nickhonner, Skyezx, Foodlol123, Protonk, Ccacsmss, Jomunro, Arjuno3, Cutechar, Jasper Deng,
Lineface, Mystical504, Davecrocker, Tide rolls, Pernoctus, MelcomRSA, Lightbot, OlEnglish, Jan eissfeldt, Ghemachandar, SasiSasi,
Thebigmc2, Taargus taargus 1, Frehley, Dreammixtr, Legobot, Luckas-bot, Smokyjohnpipe, Yobot, 2D, Dhaun, Dede2008, Fraggle81,
TaBOT-zerem, Gollobt, Legobot II, Newportm, Cyanoa Crylate, Jjl33, ArchonMagnus, THEN WHO WAS PHONE?, Fisc, Timir Saxa,
Evaders99, ‫محبوب عالم‬, Eric-Wester, AnomieBOT, Dangerousdanman, Suri252001, A More Perfect Onion, Hairhorn, Roland45~enwiki,
Stolen Account 1, IRP, Galoubet, Piano non troppo, Sorsoup, 90, AdjustShift, Skpatel20, Kingpin13, Materialscientist, ლევანი, Aff123a,
Maxis ftw, Woods229, Neurolysis, Chivasboi345, ArthurBot, LilHelpa, Obersachsebot, Nehtefa, Xqbot, TheAMmollusc, Agather, Sionus,
Mr. Prez, Melmann, Capricorn42, Drilnoth, Johnny Bin, Hobomason, Alanpratt05, Shaior, MccowattMAS229, Tad Lincoln, Grim23, Programarium, Jmundo, Slowbuteffective, Cboy676, AbigailAbernathy, Jaizanuar, Comm 212 8, C+C, GrouchoBot, Ute in DC, Wizardist,
Shirik, Mark Schierbecker, RibotBOT, SassoBot, Cresix, Wikieditor1988, Amaury, Ivan Shmakov, Hymek, Kikodawgzzz, Stratocracy,
Doulos Christos, Shadowjams, Chatul, Gnuish, Douglas W. Jones, Jinxynix, PM800, Boyhampus, RetiredWikipedian789, GliderMaven,
George2001hi, FrescoBot, Bigderom, Nageh, Merciadriluca, Atas76, Cameforu, Farawayfrom, Skylerfatfacewrwe, Sexdemon89, Porkchop28, Youarefunny, Citation bot 1, EagleEye96, Buckinghampalace101, Redrose64, Pinethicket, I dream of horses, HRoestBot, 10metreh, Jonesey95, Tinton5, Cafeduke, RedBot, Olivier Bommel, Davidx2, Beao, Xwildfire316x, Merlion444, December21st2012Freak,
‫עתיד‬-‫עם‬-‫עיר‬-‫חיפה‬-‫חיפה‬, Classfun, Martaw22, TobeBot, Trappist the monk, FFM784, Dragory, Lotje, Vrenator, Antoine854, Clarkcj12,
Henry hedden, Sarasvathi, Joshhirstwood, Notsocoolkid, Weedwhacker128, Tbhotch, Minimac, Sideways713, Mean as custard, RjwilmsiBot, Liamzebedee, Alph Bot, Liamob1993, Bobzayton489, Regancy42, Vaikulepak, Camarac, EmausBot, John of Reading, Orphan Wiki,
Racerx11, Mbekula, Freeaqingme, RA0808, WJake2009, RenamedUser01302013, Tommy2010, Lonestarcowboy, Wikipelli, Benq2010,
Iainh, Checkingfax, Ida Shaw, Illegitimate Barrister, Ramrod 63, Ὁ οἶστρος, Ionidasz, Battoe19, EJavanainen, Jallar, Chithrapriya, Encyeditor, Wayne Slam, Tailchopper99, Erianna, Chadude, Mursyids, Demiurge1000, W163, Augurar, Brandmeister, L Kensington, Schnoatbrax, Donner60, Agheefner, SPAMSLAVE, Moshi Monster Fan303, David Rolek, Noggo, Shaxelen, Bomazi, ChuispastonBot, RockMagnetist, Bad edits r dumb, Teapeat, DASHBotAV, Wikiwiki3010, 28bot, Sfung256, Rdowne52, Petrb, LM2000, Comm151student,
ClueBot NG, Gabeharvell123, Smtchahal, Better email better life, Erik Lönnrot, Gareth Griffith-Jones, Joemcboi, MelbourneStar, This
lousy T-shirt, Bulldog73, Mykebrett, Chester Markel, Another n00b, Snotbot, Ronstaufferjr, Frietjes, Cntras, Vlhsrp, Jeffm2011, Widr,
Bshurtz, Michiyoo, Wikiwhalley, Rom1sub, LBM2388, Helpful Pixie Bot, Hovn~enwiki, HMSSolent, Ukrstar, Calabe1992, Wbm1058,
Spurple, BG19bot, Xsava, Talha hasan1992, Mmwaseermohamed, Northamerica1000, Wzrd1, Doctorrace, Tomattheworthington, EdwardZhao, Hallows AG, Aktrelly, Aztrelly, Shady529, Wiki13, Chafe66, Derekmciver, Who R you?, Mark Arsten, Emailxpert, Altaïr,
Vashiva, Crazyparty16, Test1324, DGRichard, YoterMimeni, Earendil56, Matbury, Achowat, Rhaegor, Proxyma, Ahmahran, Arcandam,
Khazar2, Umpienl, MadGuy7023, Vince001001, Andrew Eugene, Openhost101, Akell567, AlexBuzaev, Mogism, 247email, Derekvicente, Dlong48, A53collins, Lugia2453, Frosty, Granichk, Davidvail, Zziccardi, Snehakmurthy, WiHkibew, Corn cheese, Scuzzawuzza123,
Raj Singh, Reatlas, BurritoBazooka, BeachComber1972, Ekips39, Kswcarey, Faizan, Kerala01, Comm212gr5, Alitlebitsexy, I am One
of Many, Mattsabe, Rockonomics, Petemclaren, Eyesnore, Jodosma, Ryanluck3, Fernwood1990, CSN13, Syamsunders, Pizzasaver,
Reedjc, MaxBowsher, Boconn45, Shahnamk, Citrusbowler, Ginsuloft, Jmjmjmie, Bodekaer, Larrysextape, Abhijith anil, Lagoset, St170e,
Gmoye101, Monkbot, AlexBuzaev82, Josie1982thebb, Jarbygardeenyia, Leegrc, Jwhite1336, Grovind2000, Hlevy2, Ksurquhart, Madman123467, User26954344524345, Allgrace20, Deonikar, CamelCase, TechJimmyMack, Jinx65555, TVleck1971, Titch-hamilton99 x,
TranquilHope, KH-1, Mario Castelán Castro, Hollyrood, Rileyandangandelle, Jawad Ashraf Warraich, IRW0, Nathangilreath11, IPUpfficia, Edawmail, Iwilsonp, TeaLover1996, Tuihjbnb, Rin borum, Reaganomics88, Jhennessy91, Rtc321, TrippieHippie, Baya younes, Getatech and Anonymous: 1409

15.2

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15.3

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