[from ‘Users' Network’; the original spelling was USENET, but the mixed-case form is now widely preferred] A distributed bboard (bulletin board) system supported mainly by Unix machines. Originally implemented in 1979--1980 by Steve Bellovin, Jim Ellis, Tom Truscott, and Steve Daniel at Duke University and the University of North Carolina, it has swiftly grown to become international in scope and is now probably the largest decentralized information utility in existence. As of late 2002, it hosts over 100,000 newsgroups and an unguessably huge volume of new technical articles, news, discussion, chatter, and flamage every day (and that leaves out the graphics...).
By the year the Internet hit the mainstream (1994) the original UUCP transport for Usenet was fading out of use — almost all Usenet connections were over Internet links. A lot of newbies and journalists began to refer to “Internet newsgroups” as though Usenet was and always had been just another Internet service. This ignorance greatly annoys experienced Usenetters.