What's the difference between a POP3 and an IMAP account?
POP3 is essentially a temporary store of your email on the server. Each time you login you empty the store by retrieving all messages. With POP3 the mailboxes are managed and stored permanently on your local computer. Once you checked your mail on the server side the mail will be removed from the server.
IMAP is a more complex protocol where the mailboxes are managed on the server side. You can access them from anywhere anytime. You can also search your mail on the server, the protocol includes a search fonction. Unless you don't delete emails from the server you can access them from different computers. You can have access to the same information at home, at work or in a cybercafé. It's also interesting when you are connecting with a Handheld to your all2all mail. Another feature of the IMAP protocol in this context is that you can download the headers of the messages only. On a slow modem or GSM connection this comes in handy ...