Protocols underlie everything done on the Internet, so it's worth taking a moment to be sure you understand them. A protocol is basically an agreement that certain parts of a system, usually different computers, will behave in certain ways in order to exchange information. A common protocol would be a client/server model, by which the client computer sends requests formatted in certain ways to a server computer, which then responds with the answer, also formatted in a specified way.
Generally, the user has no need to know the details of the protocol, but it's often useful to understand what's going on behind the scenes.
In addition to Gopher and Gopher+, common protocols on the Internet include