Is there any different between IMAP and POP?

MAP and POP are two different communications protocols that e-mail programs (such as CULink Web Client, Outlook, OS X mail, etc.) and e-mail servers (such as culink, spot, etc.) use to communicate with each other. They are the way e-mail programs interact with e-mail servers to retrieve, store, and manipulate messages.
At CU-Boulder, the preferred method of connection is the IMAP protocol. Campus users are encouraged to move away from the older, more problematic POP protocol in favor of the IMAP standard. IMAP offers several advantages over POP, including: better functionality in manipulating the inbox, the ability to manage mail folders besides one's inbox, and superior online performance.

With IMAP (Internet Message Access Protocol) you read your mail while it is still on the mail server. Because your mail remains on the server, you can access it from any IMAP-configured computer with internet access. Whether you are at work, at home, or traveling around the world, all of your messages are available to you.
POP (Post Office Protocol), on the other hand, is designed to handle offline operations. POP downloads e-mail to the PC, generally removing it from the central server. After messages are moved onto the desktop of the current local computer and deleted from the server, you then manipulate them on your desktop. Therefore, POP e-mail is only available on that specific desktop computer. e-mail stored locally using POP may not have a back-up system in place and would be vulnerable to loss in the event of a computer crash, whereas with IMAP, e-mail messages and folders are backed up nightly by ITS and are available in case of loss.
Because POP downloads messages to the local PC, it is possible to disconnect from the server while manipulating messages. Some people find this ability to work offline very useful and therefore prefer using POP. However, IMAP can also be set to work offline if desired, because messages can be moved onto the local computer as with POP. This brings up the same issues stated above, namely that messages are no longer available from other computers and that one must devise a local back-up solution.
POP also causes issues that affect all users, even those who do not use POP. For example, performance problems often occur server-wide when a just a few people using POP configure their clients to leave the mail on server. This results in enormous inboxes which severly slow down the server every time the inbox is accessed. This performance decrease affects everyone, which is not an efficient use of scarce campus IT resources.
Because of its many advantages, IMAP is the preferred method of connection for campus e-mail users. At this time both are still supported on some of the central campus e-mail servers: ucsu, spot, and rintintin. However, CULink may only be accessed via the IMAP protocol.

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