POP VS IMAP
POP (Post Office Protocol)
POP3 allows you to download copies of your email messages to your personal computer. Any changes you make will NOT be visible to other users or computers accessing the email account since you are only making changes to local copies. Consequently, messages sent, moved or deleted from a computer using POP can only be viewed on that individual computer's folders.
The copies of the email messages on the server are normally unchanged, but it is very easy to unintentionally configure your POP3 program to delete those server copies whenever you download the emails or at a future time.
POP is recommended for:
Users who prefer to keep a backup of all their messages
Users who have very limited time to be online but need to read emails
Users who need to archive permanent copies of their emails (e.g. before you terminate that email name or its hosting provider).
IMAP (Internet Message Access Protocol)
IMAP4 allows you to read emails as they appear on the hosting server. All messages and any changes you make (delete, reply, forward, move) are seen by anyone else who logs into webmail or IMAP. Depending on program configuration, messages may be temporarily saved for offline viewing.
IMAP is recommended for:
Users who connect to email accounts from many computers
Users with mobile devices with internet access, such as smart phones or tablets
Multiple users who need to access the same email account
Users who wish to always have their messages, including sent messages and message folders, saved on the server
Accessing Email: Email Programs vs. WebmailEmail Programs
An email program can be launched right from your desktop and provides you rapid access to all your emails. They also have advanced tools and features which webmail may not have.
While email access through an email program is speedy, it can be less secure than webmail if you let the program remember your password.
There are many programs to choose from, including the program included with your computer's operating system.
Microsoft Windows includes either Outlook or Windows Mail
Apple includes Mail
There are also third-party programs such as Mozilla's Thunderbird and Qualcomm's Eudora
Webmail
Webmail is often preferred due to its ease of use and the fact that it can be accessed from any computer through a web browser. Plus, it has the same advantages as IMAP.
However, webmail depends on a web browser (e.g. Firefox, IE, Opera, Chrome, Safari, etc.) which can take some time to load, access the webmail page, login and load the GUI. Also, webmail often displays a limited view of the inbox, allowing the user to view only one email message at a time.
Conclusion
IMAP is perfect for multiple users who need to access the same email account or one user who needs to access emails from multiple locations.
POP3 is perfect for quickly downloading emails and reading them offline or on the go (though you do have to be online to reply to emails). POP3 is also a great way to save copies of your emails on your personal computer.
Webmail is perfect for everyone, but does depend on a browser which can sometimes be slower and more cumbersome than a mail program.