IMAP or Internet Message Access Protocol – is an application layer protocol used for retrieving e-mail messages. The latest version is IMAP4 that is similar to POP3 but has some distinguishing features: it allows accessing messages on the server without having to download them to the local machine. You can also create, delete, and rename mailboxes, check for new messages, and search through your email messages for keywords while the messages are still on the mail server. This is the main difference between IMAP and POP3.