Here is the difference between IMAP and POP/POP3 :
Interactive Mail Access Protocol (IMAP)
With IMAP, all your mail and message folders remain on the server. Whenever you connect to the server through IMAP, you no longer poll messages but synchronize messages. The server then displays a copy of your mailbox (includes all folders). Since the original remains on the server, you can access your mail from any computer via Webmail.
Moreover, since only message headers are downloaded at first, the display of the message list is often much faster with IMAP when there are a large number of new messages on the server.
POP/POP3 (Post Office Protocol)
The POP/POP3 protocol is designed to allow you to retrieve mail from a remote machine when you are not permanently connected to the Internet.
The POP/POP3 protocol blocks your mailbox while you access it, not allowing another connection to access your mail at the same time. This means that you could have a different number of emails per mobile device or on your email software (Ex .: Outlook, Thunderbird, etc ...) in the event of a misconfiguration.
The evolution of electronic mail towards multimedia and the lack of flexibility of POP/POP3 favor the emergence of a new protocol : IMAP
Which one to choose?
This question depends only on your needs but we suggest IMAP.
Interactive Mail Access Protocol (IMAP)
With IMAP, all your mail and message folders remain on the server. Whenever you connect to the server through IMAP, you no longer poll messages but synchronize messages. The server then displays a copy of your mailbox (includes all folders). Since the original remains on the server, you can access your mail from any computer via Webmail.
Moreover, since only message headers are downloaded at first, the display of the message list is often much faster with IMAP when there are a large number of new messages on the server.
POP/POP3 (Post Office Protocol)
The POP/POP3 protocol is designed to allow you to retrieve mail from a remote machine when you are not permanently connected to the Internet.
The POP/POP3 protocol blocks your mailbox while you access it, not allowing another connection to access your mail at the same time. This means that you could have a different number of emails per mobile device or on your email software (Ex .: Outlook, Thunderbird, etc ...) in the event of a misconfiguration.
The evolution of electronic mail towards multimedia and the lack of flexibility of POP/POP3 favor the emergence of a new protocol : IMAP
Which one to choose?
This question depends only on your needs but we suggest IMAP.