The IMAP Protocol Explained
What is IMAP?
When you use IMAP then the mails will stay at the server even if they are downloaded to a computer. Any change you make locally to a mailbox of an IMAP account is reflected back to the server and then is changed in any other mail client that also uses this IMAP account. You continue to work normally within your email client. But if your motherboard goes kaputt like mine did in the summer 2012 then you just enter your username/password/servers combination into your other computer and everything is as it was before. You can even edit/view/delete your mails in the browser of your choice.
And what about iCloud?
The mail part of iCloud uses the IMAP protocol.
What are the benefits of IMAP?
Your mails can be accessed from different computers and all have the same data.
What are drawbacks of IMAP?
IMAP is a bit more complicated than POP and of course nothing is perfect. So read about the drawbacks and decide which are important to you.
- Quotas: Space on a server is always expensive. If you get many mails quota space may fill up very fast.
- Because the IMAP protocol is a bit more complicated there are some variations in the wild - notably Gmail.
- If someone hacks your account and you haven't downloaded your email to your computer, then the mails are gone. As with every other kind of data it's your job to do due diligence.