

This definition is from the ComputerUser.com High-Tech Dictionary:
Internet Message Access Protocol. A protocol that allows a user to perform certain electronic mail functions on a remote server rather than on a local computer. Through IMAP the user can create, delete, or rename mailboxes; get new messages; delete messages; and perform search functions on mail. A separate protocol is required for sending mail. Also called Internet Mail Access Protocol.
On peut donc le considérer comme un moyen de stocker des données. Pour l'utiliser il vous faut un serveur IMAP comme Cyrus, Courier ou UW.