By Paul Thurrott
Sometimes described as the best-kept secret on the Internet, the IMAP e-mail protocol might more accurately be thought of as “Exchange Server for the rest of us.”
IMAP, which stands for Internet Message Access Protocol, is a more modern protocol than POP3 (POP stands for Post Office Protocol). POP3 is far more commonly used, but is also far less versatile.
POP3 more or less assumes you will only access your e-mail from a single machine. When you check a POP3 e-mail account, your mail is typically downloaded to the PC and the messages are then removed from the server.
In this sense, POP3 is essentially a client-side e-mail solution. But if you experience any problems with the client machine, your e-mail data could be lost forever because the server-based copies were deleted.
The benefits of IMAP over POP3
IMAP is a superset of POP3. For example, both standards support offline mail access and are based on open standards.