E-Mail

E-Mail, in computer science, abbreviation of the term electronic mail, method of transmitting data or text files from one computer to another over an intranet or the Internet. E-mail enables computer users to send messages and data quickly through a local area network or beyond through a nationwide or worldwide communication network. E-mail came into widespread use in the 1990s and has become a major development in business and personal communications.

E-mail users create and send messages from individual computers using commercial e-mail programs or mail-user agents (MUAs). Most of these programs have a text editor for composing messages. The user sends a message to one or more recipients by specifying destination addresses. When a user sends an e-mail message to several recipients at once, it is sometimes called broadcasting.

The address of an e-mail message includes the source and destination of the message. Different addressing conventions are used depending upon the e-mail destination. An interoffice message distributed over an intranet, or internal computer network, may have a simple scheme, such as the employee’s name, for the e-mail address. E-mail messages sent outside of an intranet are addressed according to the following convention: The first part of the address contains the user’s name, followed by the symbol @, the domain name, the institution’s or organization’s name, and finally the country name.

A typical e-mail address might be sally@abc.com. In this example sally is the user’s name, abc is the domain name—the specific company, organization, or institution that the e-mail message is sent to or from, and the suffix com indicates the type of organization that abc belongs to—com for commercial, org for organization, edu for educational, mil for military, and gov for governmental. An e-mail message that originates outside the United States or is sent from the United States to other countries has a supplementary suffix that indicates the country of origin or destination. Examples include uk for the United Kingdom, fr for France, and au for Australia.

E-mail data travels from the sender’s computer to a network tool called a message transfer agent (MTA) that, depending on the address, either delivers the message within that network of computers or sends it to another MTA for distribution over the Internet (see Network). The data file is eventually delivered to the private mailbox of the recipient, who retrieves and reads it using an e-mail program or MUA. The recipient may delete the message, store it, reply to it, or forward it to others.

Modems are important devices that have allowed for the use of e-mail beyond local area networks. Modems convert a computer’s binary language into an analog signal and transmit the signal over ordinary telephone lines. Modems may be used to send e-mail messages to any destination in the world that has modems and computers able to receive messages.

E-mail messages display technical information called headers and footers above and below the main message body. In part, headers and footers record the sender’s and recipient’s names and e-mail addresses, the times and dates of message transmission and receipt, and the subject of the message.

In addition to the plain text contained in the body of regular e-mail messages, an increasing number of e-mail programs allow the user to send separate files attached to e-mail transmissions. This allows the user to append large text- or graphics-based files to e-mail messages.

E-mail has had a great impact on the amount of information sent worldwide. It has become an important method of transmitting information previously relayed via regular mail, telephone, courier, fax, television, and radio.