What is Pop3?
Pop3, short for Post Office Protocol (version 3), is a prevalent method of remotely retrieving your emails from somewhere other than your web-based email account over a TCP/IP connection. For example, instead of accessing your emails from a web browser (IE, Chrome, Safari, etc.) on your desktop computer, you will be able to access them from any Mobile Device (e.g. iPhone, Android, etc.) or Local Email Client Program (Outlook, Apple Mail, etc.)
What features does Pop3 have?
Pop3 is a simple, stripped down way to remotely access emails. It allows the functionality of download-and-delete emails and does not use two-way communication.
Devices that use Pop3 often have an option to leave mail in your web-based email account after download. As a general rule, e-mail clients using Pop3 connect to your web-based account, retrieve your messages, store them on your remote client as new messages and then deletes them from your web-based account.