This is a question I get asked a lot as an IT Specialist. It’s best answered by explaining the difference between IMAP and POP.
But before I can explain the difference, lets have a refresh on the basics of how email is received.
When someone sends you email, it doesn’t come straight to your computer or phone. It actually goes to the web server where your email account is hosted, and sits there. Then, when you open your email client, it connects to the server.
At this point is where the differences between POP and IMAP become apparent.
POP stands for Post Office Protocol, and was the first email protocol used. (Sometimes you might see a number 3 at the end for POP3, which just stands for version 3). POP hails from a day when we didn’t have computers in our pockets, TVs, fridges, etc… and email was checked from a single device. POP is very straight forward, and not very complex; it searches the server for new mail, downloads a copy to your email client, then removes it from the server.
IMAP stands for Internet Message Access Protocol. IMAP is much more complex than POP and turns your email server from a temporary place where new mail sits, into a central access point for email.
It’s easier to think of IMAP less like a way to “get new mail” and more like a Cloud Storage. When new email comes to your server, it is automatically put into the IMAP folder called Inbox. Whenever one of your devices uses an email client to check for new email, it looks at the server to see if there are any changes to the folder Inbox and updates the Inbox on that device with the changes (New email).
But it doesn’t just stop there.
The IMAP account on the server syncs all of your folders. This includes Sent, Drafts, SPAM, and any custom subfolders you might have made yourself. Anytime one of those folders changes on one device, the IMAP account is updated on all of your devices connected to it.
You Open your mail on your iPhone. You receive 3 new emails and decide to read 1 of them, and reply to it. You go home and open Outlook on your PC. You will see the 2 new, unread emails, and the 3rd one already read, with the reply you created sitting in the Sent folder.
POP might still have a place in specific situations where you want the security of email only being accessed on 1 device. But for the majority of us smartphone wielding, tablet hording masses, IMAP is the clear winner.