Electronic mail, often abbreviated to e-mail, email or eMail, is any method of creating, transmitting, or storing primarily text-based human communications with digital communications systems. Historically, a variety of electronic mail system designs evolved that were often incompatible or not interoperable. With the proliferation of the Internet since the early 1980s, however, the standardization efforts of Internet architects succeeded in promulgating a single standard based on the Simple Mail Transfer Protocol (SMTP), first published as Internet Standard 10 (RFC 821) in 1982.
Modern e-mail systems are based on a store-and-forward model in which e-mail computer server systems, accept, forward, or store messages on behalf of users, who only connect to the e-mail infrastructure with their personal computer or other network-enabled device for the duration of message transmission or retrieval to or from their designated server. Rarely is e-mail transmitted directly from one user's device to another's.
While, originally, e-mail consisted only of text messages composed in the ASCII character set, virtually any media format can be sent today, including attachments of audio and video clips.
The spellings e-mail and email are both common. Several prominent journalistic and technical style guides recommend e-mail, and the spelling email is also recognized in many dictionaries. In the original RFC neither spelling is used; the service is referred to as mail, and a single piece of electronic mail is called a message.
E-mail predates the inception of the Internet, and was in fact a crucial tool in creating the Internet.
E-mail started in 1965 as a way for multiple users of a time-sharing mainframe computer to communicate. Although the exact history is murky, among the first systems to have such a facility were SDC's Q32 and MIT's CTSS.
E-mail was quickly extended to become network e-mail, allowing users to pass messages between different computers by 1966 or earlier (it is possible that the SAGE system had something similar some time before).
The ARPANET computer network made a large contribution to the development of e-mail. There is one report that indicates experimental inter-system e-mail transfers began shortly after its creation in 1969. Ray Tomlinson initiated the use of the @ sign to separate the names of the user and their machine in 1971. The ARPANET significantly increased the popularity of e-mail, and it became the killer app of the ARPANET.
Messages are exchanged between hosts using the Simple Mail Transfer Protocol with software programs called mail transfer agents. Users can download their messages from servers with standard protocols such as the POP or IMAP protocols, or, as is more likely in a large corporate environment, with a proprietary protocol specific to Lotus Notes or Microsoft Exchange Servers.
The usefulness of e-mail is being threatened by four phenomena: e-mail bombardment, spamming, phishing, and e-mail worms.
Email spoofing is a kind of forgery. Mails appear to be sent from a known sender but they are actually not so. Spoofing involves forging the email headers, by altering the header information.
E-mail privacy, without some security precautions, can be compromised because:
- e-mail messages are generally not encrypted;
- e-mail messages have to go through intermediate computers before reaching their destination, meaning it is relatively easy for others to intercept and read messages;
- many Internet Service Providers (ISP) store copies of your e-mail messages on their mail servers before they are delivered. The backups of these can remain up to several months on their server, even if you delete them in your mailbox;
- the Received: fields and other information in the e-mail can often identify the sender, preventing anonymous communication.
For More Information: E-mail Background Information
Source: Wikipedia (All text is available under the terms of the GNU Free Documentation License)