When you check for new email messages, your email app talks to the email server using one of two protocols: POP3 or IMAP. What’s the difference between the two, and which should you use?
The original incoming email protocol, POP3 (Post Office Protocol 3) is a simple way to check email.
When you configure your email client to check email using POP3, it downloads all email messages from your email server and marks them to be deleted from the server.
Advantages: Emails are downloaded and stored on your local devices (eg. your phone, tablet and desktop/laptop computer) and are automatically deleted from the server, automatically freeing up space on your server mailbox.
Disadvantages: Your emails and folder do not get synchronized to your phone or other devices or the server.
IMAP (Internet Message Access Protocol) gives you live access to all your email messages. Designed as an improvement over POP3, IMAP is the way to go if you access email from more than one device. With IMAP, your messages stay on the server until you delete them in your email client. Everything you do with email messages syncs with your email server. When you read a message (or mark it as read), it’s automatically marked as read on the email server.
Advantages: Synchronizes all folders and emails with the server and the devices (eg your phone, tablet and desktop/laptop computer) on which you setup the email account.
Disadvantages: Your space on the server is limited per email account to 500 MB. If you keep all your emails on the server, especially those with attachments, your email account will eventually run out of space, at which point you would be not able to receive any more emails until you freed up some space by deleting old emails.