What are they? In short, both IMAP and POP3 are just the way in which your emails are received. Once received they can be downloaded into an email client such as Outlook or Thunderbird, or onto a mobile device.
What is IMAP?
Short for Internet Message Access Protocol. When you open your inbox using IMAP you are viewing your emails in their mailbox on the server without actually downloading them. This means that if you read an email on your home PC, then want to check it again later on your mobile phone, you can. It will be visible on both devices. The disadvantage is that you may decide you need a larger mailbox limit, as instead of being download onto local storage (as with POP3), the emails remain in your mailbox on the server unless you specifically instruct a download. If you would prefer to be able to view your emails from multiple devices, then an IMAP account is probably the best thing for you.
What is POP3?
Short for Post Office Protocol 3. If your email client or mobile device uses POP3, the emails are downloaded onto local storage, ie. your computer or mobile device. The emails have effectively “moved” from the server onto the local storage. This means they are now unavailable to be viewed elsewhere (unless in your settings you have ticked “keep a copy of the email on the server”). For example, if you have a POP3 email account and open emails on a PC, when you try to open the same emails on your mobile phone, you will find they are not there. This is because they have been downloaded onto the local storage of your email client (ie. your PC). What you will find though, are any emails which have been sent to your inbox since you last checked it using your PC. Upon opening, these new emails will download to your mobile device. If you want to keep it simple, and just check your emails on a single device or computer, then POP3 would be a sensible choice for you. As the emails are downloaded from the server to your local storage every time you open them, the server is effectively “emptied”, so you are unlikely to ever reach your account mailbox limit.
