errr
POP3 and IMAP4
IMAP4
IMAP4 and POP3
Internet Messaging Access Protocol 4 (Netscape)
Internet Message Access Protocol (commonly known as IMAP or IMAP4,
993
IMAP4
Some email servers can be accessed via POP3 (or IMAP4). You can install an email client, and access any of these, as long as they have the option to configure POP3 or IMAP4. Or you can configure a Web-based email system, to get email from other accounts. Once again, this assumes the servers you want to access have the option to access either via POP3 or via IMAP4. I am not entirely sure which servers have this option; GMail does, but I am not sure about the others.
well the advantegas are you win and the disadvanteges are you get hurt
application layer
IMAP4 by design keeps your emails on the server. POP3 accounts can be configured to leave copies on the server.