What is a POP or POP3 mailbox?

POP (or POP3) is an early email protocol used to access mailboxes. It’s very simple and remains popular despite its age, however many users are now starting to find that IMAP better meets their needs. POP box is a term that is widely used but is not accurate, throughout our documentation you’ll find them referred to as ‘mailboxes’ or ‘mail accounts’.