Because electronic mail is so useful, countless graphical interfaces have been created for it. While you can use SMTP directly to compose and receive mail, it's a very difficult and unforgiving interface to master. IMAP allows a user to store his mail in a central location. Mail messages remain on the server until the user deletes them. Programs like Pine and the latest version of Netscape can interact as IMAP mail clients.
POP allows a user to contact the mail server and download mail to a local computer.
Although the POP standard permits continuous mail storage, servers can also be configured to delete mail from the user's mail queue once it's been downloaded to a receiving terminal. The mail stays resident on the receiving terminal until the user deletes it. POP does not permit a user to create folders on the mail server. With POP you can create, send, retrieve and potentially store mail on the server. Programs like Eudora and Netscape interact as POP clients.