IMAP vs POP3
What is IMAP?
Internet Message Access Protocol (IMAP) is a standard protocol for accessing email from your local computer. IMAP is a protocol in which email is received and held for you on our servers. You (by using your email client, such as Outlook Express, Thunderbird or Eudora) can view just the header information, which includes the sender and subject, allowing you to decide whether to download the entire message or not. You can also create and manipulate folders or mailboxes on the server, delete messages, or search for certain parts or an entire note.
What is POP3?
Post Office Protocol 3 (POP3) is also a standard protocol for receiving email and is also a client/server protocol in which email is received and held for you on our servers. With POP3, your mail is saved in a mailbox on the remote server until you check your mail. When you check your mail, all of the mail is immediately downloaded to your computer and is usually no longer stored on the server.
What's the Difference?
IMAP can be thought of as a remote email service, while POP3 can be thought of as a "store-and-forward" service. Ultimately they both accomplish similar tasks but often one will suit your needs better than the other.
What are the Benefits of IMAP?
Since you can view just the header information without downloading the entire message, you can delete large messages without wasting time and bandwidth downloading them. Also, because the messages remain on the server, you can access the same email accounts and the same emails from multiple computers or at multiple locations. With the messages remaining on our servers, you also don't have to worry about losing them if your computer crashes.
What are the Benefits of POP3?
Because all of your messages are downloaded immediately, after you've checked your inbox you can disconnect from the internet and continue reading your new email. This isn't always the case with IMAP, although many popular mail clients like Outlook 2007 and Thunderbird do now offer "Offline" modes for IMAP. Because with POP3 your messages are downloaded to your computer, you also do not need to worry about accruing disk usage charges because the messages do not stay on our servers.
What are the Drawbacks to IMAP?
Unlike POP3, IMAP generally requires access to the internet during the time that you are working with your mail. Increasingly, modern mail software like Outlook 2007 and Thunderbird can however be configured to allow you to manipulate and view downloaded copies of email while you're offline - synchronizing your changes with the stored mail on the server the very next time you connect. One other drawback because the messages are stored on the server is that it becomes easier to go over your disk quota. You can reduce this risk by taking specific steps to not leave your Sent Mail, Drafts or Trash on the server.
What are the Drawbacks to POP3?
The major drawback to POP3 is that it is an older protocol that was designed before people were able to easily send large emails with attachments. Because POP3 downloads all the mail on the server at once, people are occasionally unable to successfully receive their messages because POP3 will get stuck or disconnect when trying to download large messages. To fix this people will either need to contact tech support or log onto our webmail system to delete the large messages themselves. Also, if you use POP3 and are traveling or check your mail from multiple locations, you will often not be able to view your old email, because the messages only exist on the computer on which you originally downloaded the mail.