I am one of the many who ask the same question : what is the difference between POP and IMAP email settings?
POP is short for Post Office Protocol, a protocol used to retrieve e-mail from a mail server. Most e-mail applications use the POP protocol, although some can use the newer IMAP.
As per my research, IMAP offers a two-way communication between your hosting mailbox and your email client. When you perform an action on your mailbox, it is immediately reflected on the email clients and mobile devices viceversa. Example, when you are at work and you begin to create a message and save it, it will still be in intact when you log in from a different client or area or different gadget.
Starting today, I will use IMAP from now on. I access from emails from my Macbook in the office, Netbook when I go out, Blackberry Bold and my PC desktop at home. I am used to using POP account, I guess its time to make a move because IMAP simply provides a better method to access my mail from multiple devices through two-way syncing capabilities between my mail clients and the our hosting mailbox.
Just take note though that since IMAP saves all your messages on the server, be sure to frequently clean up your mailbox, deleting old messages.