Neat, this lesson showed that something that was around before WWW is still here today and still in use. Harley Hahn does give a great, fact-filled tutorial about usenet.
I visited the Library usenet group: soc.libraries.talk. Not a lot of activity—Activity Low--only 20 recent authors. Much as it says its all things library related, I found an obvious spam posting that made it into the group. It was most used in 1996 and 1997, actually, there was lots of usage from 1994 through first months of 2000, then it really drops off, hardly ever getting up to 100 posts per month after that.
Since you have to pay to access Harley Hahn's Internet Yellow Pages, Google Groups is a great free way to find usenet groups. I had a lot of fun as you can search for groups on anything—vampires, authors, movies, cars (I searched my car make & model), etc. Main thing to keep in mind is that all the information is informal, undocumented, opinions. As groups also have RSS feeds, Usenet seems to be very similar to the news groups/social marketing sites we learned about in Library 2.0: Bloglines, Technorati, Topix, etc.