What is the Difference Between POP3 and IMAP Email and Do I Really Need to Know This?

Email is an inescapable part of life. Billions of emails fly through cyberspace every day. Miraculously, they ends up at their destination without much effort on the part of the recipient. Every once in a while though, users want to tweak how they receive their email. They want to forward from one address to another, for example, or set up web email to work with an email program on a computer. This is when knowing the difference between POP3 and IMAP becomes important.

The process of sending email begins with a mail server. This is a computer on a network specifically for sending and receiving emails. It uses the SMTP (simple mail transfer protocol) to do this.

At some other node on the network there is a person who wants to send or receive email. They usually have a personal computer. Everyone who receives email uses an email client. Outlook for Windows or Eudora for the Mac are a couple of examples of clients. This is where POP3 and IMAP become involved.

POP3 (post office protocol)

POP3 is an older technology that retrieves the mail from the server and puts it on the local computer. POP3 was the most popular protocol when dial-up computing was in fashion. The user logs on to the server and downloads email to an client (Outlook). The email is deleted from the server and exists only on the users computer. It can be read and responded to while the user is off line. The responses or newly generated email that needs to be sent by the user is held on the local computer until the next time the user logs on to the server.

IMAP (Internet Message Access Protocol)

IMAP is newer technology. It works much the same way as POP3 except that IMAP transfers more information. When email is received on the server the user is able log on to the server. From here the mail can be viewed, marked as read, or deleted. The user can also create and manipulate folders, or search for certain text within email. The information about these choices remains on the server. With IMAP the user can decide which, if any, emails to download. The information is stored on the server until it is deleted by the user or the mail exceeds the allowed capacity.

Which is better?

When dial up connections were the norm the choice between POP3 and IMAP protocols was more difficult. POP3 allowed users to work offline which saved on connection costs. It offered the security of having the email stored on a local machine. Although IMAP messages were easier to manage IMAP required an network connection to access email and the messages were remotely stored and not easily accessible.

Computer user have become accustomed to constant broadband connections. Because of this they have become comfortable with online services such as Gmail or Hotmail that don't download to a local computer at all. The question of access to a mail server that made POP3 attractive no longer seems relevant. The ability of IMAP to store more information and to allow users to access mail from multiple locations has made it the clear leader for users who still want the option of storing email on their hard drives.