A program that can be used to display web pages. Netscape is a browser. An electronic message center. Most bulletin boards serve specific interest groups. They allow you to dial in with a modem, review messages left by others, and leave your own message if you want.
Bulletin boards are a particularly good place to find free or inexpensive software products.
In the United States alone, there are tens of thousands of BBSs. The names of successive domains are used to form a unique name by which the computer is known to the network. A structured name for a computer in a network, in the form melvyl.ucop.edu. Uniqueness is ensured by having a hierachy of naming authorities, each one responsible for approving the names in its immediate domain. Often the last step necessary to have your own copy of a file.