These two funny words refer to the way that your email client, whether that is on your home computer, laptop, smartphone or tablet, talks to the server that holds the emails.
The main difference between POP3 and IMAP is that POP3 downloads the email from the server onto the device, whereas IMAP just reads the email on the server.
Why does this matter?
If you choose IMAP, then you can read your emails from multiple devices, and any changes you make automatically update on all devices. If you lose your device, then the emails will still be on the server. You will need an internet connection to read your emails and your emails will count towards your email storage space, however you can save space by archiving emails or saving them to local storage.
If you choose POP3 then you can read your emails offline. They’re stored on your computer and you don't use up your email server storage space. On the downside, you can only download an email to one device, and if you lose that device you lose your emails too.
Which one should you choose?
We recommend IMAP as the protocol that you should use, so you can check your emails on your computer, via webmail, and smartphone depending on where you are. Most devices will have internet access through WiFi or 3G/wireless, therefore being able to access your emails offline through POP3 isn’t as important as it used to be.