Before doing all sorts of investigating about the nature of POP vs. IMAP, it might not be a bad idea to consider whether or not the default configuration you encountered before finding this article offers what you need. Most modern email clients allow you to choose which delivery method you would like to use to receive your email, while services like Gmail allow you to use a web interface, as well as POP or IMAP. These two protocols exist out of necessity, and together they support a number of workflows that allow you to choose the best way to interact with email.
POP3
The biggest downside to POP is if you don’t have the server configured to store your email. If you download all of your email locally and something happens to your computer, you’ve lost those messages forever. Because storage is cheap everywhere now, and email takes up very little space (for most people), there’s not a good reason not to store your messages on the server. If you’re using POP in a smartphone and storage is an issue, maybe if you’ve got an 8GB iPhone filled with music and games for example, then storage may become an issue. For most users, however, storage is something that we have an abundance, so storing your email locally is a great way to make sure you always have access to your email.
IMAP
These days, it seems like most of us have fairly constant access to internet. Should email be treated any differently than any other form of electronic communication that we receive? Internet Message Access Protocol (IMAP) allows users to access email from anything, as long as you have the username and password. With IMAP, the email lives on the server and you have access to some basic information about every email in your Inbox. When you want to see and interact with the email, the email is temporarily downloaded but not really stored on the machine you are using. The biggest benefit to IMAP is the ability to quickly access your email from just about any device — as long as you have a decent internet connection you’re never more than a moment away from your entire inbox.Unfortunately, if you’re without a fast connection or if you are somehow without internet entirely (-gasp-), you’re going to have a bad day. Most IMAP clients will grab a week or two of email headers and store that information locally, but will not grab images or attachments. If you need to search your inbox for something, and that email is more than a few weeks old, you’ll find that the headers for your email will skip entire weeks of received messages unless you’re connected to the net.
Switching is easy
There’s also nothing that says you have to pick one and stick with it. Even Gmail, one of the most popular free email services in the world, makes it easy to choose POP or IMAP and allows you to switch between them as you see fit. You can choose the service the best fits your needs, but ideally your email should exist as a service that requires very little maintenance and configuration once it has been setup and used.