IMAP

IMAP, short for Internet Message Access Protocol allows users to access their email that is on a remote server from their computer. Almost all e-mail clients support this protocol, but many of the free webmail services, with exception to Gmail, do not support IMAP or POP3.

Features

IMAP supports connected and disconnected modes. In connected mode, the e-mail is still stored on the other server and the e-mail client reads it off of the server. In disconnected mode, the e-mail messages are downloaded to the remote computer and can be read at any time without an Internet connection or with a connection.

Advantages

IMAP has several key advantages, such as the ability to connect multiple clients to the same mailbox, whereas POP3 can have a max of one. It also features a built-in extension mechanism, in which it may be expanded at any point in the future. With IMAP the messages can be downloaded instantly, instead of having to request the messages manually.