Most email providers (but NOT all!) such as iCloud, Gmail, webmail/cPanel accounts, and a host of other providers offer two ways to setup your email when using an email client such as Apple Mail, Outlook, or your smartphone or tablet of choice. The more well-known among the general population seems to be POP (Post Office Protocol) and the other is IMAP (Internet Message Access Protocol). Here's a simple breakdown of what each can and cannot do for you and the benefits of using one over the other...
POP (Post Office Protocol) When using this method, messages are pushed to a device (computer, phone) and they sit there. Depending on your email client setup depends on how this really works, but in short, messages get shoved to all of your devices and you deal with messages on each and every device - or whichever device pulls them from the server first. POP is a one-way street. This email setup method is very client/device specific and what you do on one device (reply or send a new email), is NOT reflected on any other device you have. POP email is backed up only as far back as the storage capacity of your email account and/or your own computer's hard drive or backup. Lost your computer data? Then you've lost your email (possibly, not always; POP always depends on the specific setup you use).
IMAP (Internet Message Access Protocol) For email users that like their email to be "the same", or synced, across all devices, IMAP is the sure-fire way to go. IMAP keeps your email client synced with the email server. Regardless of the device you are on, if you delete an email in the inbox, it deletes it across all devices. This method is helpful when trying to manage large volumes of email and when replying from various devices throughout the day. Better yet, you can create folders using the IMAP account and they will sync across all devices keeping all of your email with you at all times. IMAP accounts are backed up with the server they sit on - most web-based email accounts and other large vendors like Apple and Google backup their servers redundantly so even if you lose all of your computer data, if you've setup IMAP properly you can have your email back rather quickly. IMAP is a two-way street. Users on an Exchange Server have the same functionality as IMAP accounts.
So why would someone use POP? While it is not recommended for most heavy email users or users that email over a variety of devices, it is sometimes the ONLY option an email provider offers. However, one may choose to use POP over IMAP if s/he wants an original copy of every incoming message s/he gets on every device s/he owns (note that depending on device settings and server settings this can sometimes not be achieved).
Why should someone using POP convert to IMAP? Someone who uses multiple devices to check, respond to and send emails would benefit greatly from IMAP due to its cross-device access. No matter what device you are on you can see your email in the same way. You can still have computer-based folders for emails that don't need to sync across all devices if storage is an issue.
WE CAN HELP!
Four Points Consulting provides email services to many clients. We help with basic server side website and email hosting, and we are providers of Google Apps / G Suite. We can assist with Office 365 and other setups as well. We are well-versed in migrating accounts, setting up a variety of devices, and everything else related to email needs. Contact us today!