NetNews is a general term to cover internet discussion groups that evolved from usenet..

Usenet was established in 1980 for exchange of information on various topics.
It was structured as hierarchies - under nine major areas:

• comp - computer-related discussions (comp.software, comp.sys.amiga)
• humanities - fine arts, literature, and philosophy (humanities.classics, humanities.design.misc)
• misc - miscellaneous topics (misc.education, misc.forsale, misc.kids)
• news - discussions and announcements about news (meaning Usenet, not current events) (news.groups, news.admin)
• rec - recreation and entertainment (rec.music, rec.arts.movies)
• sci - science related discussions (sci.psychology, sci.research)
• soc - social discussions (soc.college.org, soc.culture.african)
• talk - talk about various controversial topics (talk.religion, talk.politics, talk.origins)
• NNTP - Net News Transfer Protocol was set up in 1986 to support usenet news over the internet.
• alt - An unorganized area which included a variety of topics

Today there are many kinds of net forums from discussions of problems in particular application programs to family forums for people working on genealogy that serve a similar function.

Google Groups

Links:
Usenet - Wikipedia, the free encyclopedia
Network News Transfer Protocol - Wikipedia, the free encyclopedia