Electronic mail, or e-mail, is the Internet's most widely used feature today. E-mail is a private communication between two users who have e-mail accounts. E-mail is designed for the transmission of text messages from one Internet user to another user. Like mail delivered by the Post Office, Internet e-mail allows you to address your messages to a particular person. E-mail messages are generally sent from and received by mail servers - computers dedicated to processing and directing e-mail. When sent, it eventually arrives in that person's e-mail box (generally an Internet-connected computer where he or she has an account) and your recipient can read, forward, or reply to the message.

Internet e-mail addresses follow a certain convention, as follows:
username@host.sub-domain.domain.first-level-domain
Where username is the name of the account with the computer, host is the name of the computer that provides the Internet account, sub-domain is an optional internal designation, domain is the name assigned to the host organization's Internet presence, and first-level-domain is the two- or three-letter code that identifies the type of organization that controls the host computer.