POP3 and IMAP4 are considered standard mail access methods or protocols. They are used to access messages stored on a mail server. Because they are industry-recognized standards, literally dozens of different "clients" (the GroupWise client being just one of them) support the ability to access your mail on a mail server through one or both of these protocols. POP3 and IMAP4 are never used when you want to send mail; they are strictly used for retrieving mail items stored on a server. Also, when the GroupWise client communicates with a GroupWise post office, it does not use POP or IMAP, but a proprietary encrypted and compressed connection directly to the post office agent. So, with that high-level introduction on what POP3 and IMAP4 are, let's explore which protocol could best meet your needs when accessing your Internet accounts mailbox.