POP or IMAP: Which Should I Use and Why?

PC email programs have two ways to get your mail from the server, called POP and IMAP. Most programs, including Netscape, Outlook, and Outlook Express, can be configured either way. The EE Department supports both.
 
IMAP keeps the mail folders on the server, and it is compatible with Webmail and Pine. You can switch between different computers, mail programs, Webmail, and Pine, and they will all show the same mail folders and have the same messages marked as seen. If you want this flexibility, use IMAP.
POP keeps the mail folders on the PC. This has some advantages for speed and offline use, but requires that you always read mail with the same PC, which may be true if you carry a laptop around, or always read your EE Columbia mail from the office.

Be careful using a mail program on someone else's computer unless you know which protocol it is using. You do not want POP to move your mail to that PC where you cannot get it later from elsewhere. For a quick check of new mail, the EE Web-based email system is always safe.

Summary of IMAP Features

The IMAP Inbox is stored on the EE mail server. To view it, you must have a network connection open. You can use other mail folders on the mail server, in addition to the Inbox.
 
All the mailboxes on the EE mail server are backed up, and can usually be recovered, especially within the first few days after loss.

If you have a lot of mail, look for a way to store mail into "local" folders on your PC's hard drive, where you probably have much more disk space available. You should be able to drag and drop groups of messages and whole folders from the imap server to local folders. You will have to wait for the messages to download when you do this.

Summary of POP Features

The POP Inbox is stored on the PC's hard drive. The PC email program contacts the server solely to pick up new mail. Otherwise, all mail folders are on the hard drive. Access to mail folders on the hard drive can be much faster than access to IMAP folders if your network connection is relatively slow, like a dialup line.

The mail is mostly not backed up on the EE mail server. It's not on AcIS's server long enough. You must back up the mail folders the same way you back up any files on your PC.

Look for a configuration option to leave mail on server. The most trouble-free choice is not to leave any on the server at all. Certainly, do not simply leave on server indefinitely, because nothing will clear out the mail, and eventually it will fill all your space and you won't be able to get new mail. Leave on server only if you have some plan to clear it out in the near future.

Extra Features

The makers of PC email programs have tried to offer ways around the limitations of POP and IMAP by simulating to some degree what the other protocol does.

Do you want to read mail offline? POP is the obvious solution, but may not be ideal for you for some other reason. Most email programs provide for an offline mode with IMAP. The program copies your entire Inbox, and any other mail folders you specify, to local disk, so that you don't need to be on the net to see them. Later, when you are online again, the email program will synchronize changes you made in the local copy with the copy on the EE mail server. Offline mode does not always work smoothly, and some email programs make it easier than others.

Do you want to use two PCs to read mail, one at home and one at work? IMAP is the obvious solution, since it will show you the same Inbox at both places. But some email programs provide a way to do it with POP, by leaving mail on server for a specified number of days. As long as you use each PC within that many days, each will be able to maintain a complete copy of your mail. They are each looking at their own copy of Inbox, so mail seen or deleted on one is not marked seen or deleted on the other PC.