Usenet offers you thousands of specific special interest groups. If you have an interest, no matter how arcane, you can probably find a group of like-minded people to share your thoughts with. Usenet is like thousands of bulletin boards you can read, respond, and post your opinions and information to. There are many Usenet browsers (Netscape has one built in.
My favorite is Nuntius. Although Nuntius has a somewhat primitive interface, it is quite powerful.
Another popular Usenet browser is NewsWatcher.
Netscape also has a built-in news browser that you can access by choosing "Netscape News" under the "Window" menu.