IMAP

Internet Message Access Protocol is used by email clients to retrieve messages from a mail server. IMAP is the protocol that IMAP clients use to communicate with the servers, and SMTP (Simple Mail Transfer Protocol) is the protocol used to transport mail to an IMAP server.

The current version is IMAP4. It is similar to POP3 (Post Office Protocol version 3), but offers additional features. For example, the IMAP4 protocol leaves your email messages on the server rather than downloading them to your computer. If you wish to remove your messages from the server, you must use your mail client to generate local folders, copy messages to your local hard drive, and then delete and expunge the messages from the server.