They can do all sorts of things, such as obtain files, games, other software. There's a ton of free programs on bulletin boards. There's a lot of great stuff on the Internet you could put in the newsletter. The big difference is that the bulletin board cannot connect to other computers around the globe. It allows people to conference on certain topics in a region or around the nation.
Internet goes beyond the bulletin board.
Most interlink programs are migrating toward a client- server. There are two interfaces. Mosaic is similar to Microsoft Windows. It is not available to blind users with DOS screen readers. Links is, but there are lots of tricks to using Links.