If the web is the most glamorous protocol, the mail / news protocols are the work horses of the Internet. These protocols are designed simply to transfer text from computer to computer. There are a number of related protocols, including MNP, SMNP, POP, and on and on... It really isn't that critical to understand the difference between them. The important thing to understand is that when you are reading mail or news, whatever program you use to do this is using a mail/news protocol.