Our new mail servers now support both POP and IMAP protocols, which may lend one to ask “Which should I use”? (almost all email client software will support both) Here is a guide:
POP (Post Office Protocol) was the most commonly used method of retrieving email from a mail server for a long time. On a POP mail server, all of your new email is downloaded to your computer when you check for mail.
POP is still a good choice if you use just one computer for email. Since all your email is kept on your own computer, searching through your mail is much faster. Plus, you can access your email when your computer is off-line. POP users also do not have to worry about disk quotas on the mail server, since the email is removed from the server after you download it.
IMAP (Internet Message Access Protocol) is system where your email is stored on the mail server, and your email client software simply views the messages that are on the server and displays them. Any mail folders that you create in an IMAP account are actually created on the server, and not on your computer. Most modern email services (like Gmail) are based on IMAP
IMAP is a great choice if you regularly use more then one device to check your email (such as a computer and a smartphone), or if you are a regular Webmail user. Since the email is kept on the server, when you connect from any computer you can see all your mail folders and the email stored in them. If you compose and send a message from one device, that message will also show up in the “Sent” folder in your other devices.