Definition of Usenet

1. a set of thousands of newsgroups (discussion forums) distributed via the Internet (formerly distributed through the Usenet wide-area network). Newsgroups have descriptive names such as sci.astro. amateur and are arranged into hierarchies (classifications), of which the main ones are:
   

   news.	for announcements about Usenet itself;
   comp.	for computer science and technology;
   sci.	for other academic topics (including humanities);
   soc.	for cultural interest groups;
   rec.	for hobbies and sports;
   talk.	for wide-ranging discussions, often heated;
   misc.	for a few topics that don't fit elsewhere;
   alt .	for trial newsgroups and "alternative" topics.

   
   Usenet has no headquarters; the messages are copied back and forth among numerous servers. However, in recent years, participation in this network has declined, and many users prefer to access the newsgroups through https://groups.google.com (Google Groups). This sometimes creates the false impression that Google runs the whole system.
2. a wide-area network for UNIX machines that formerly exchanged files by modem through the UUCP ("UNIX-to-UNIX copy") command. Usenet addresses were of the form
   psuvax!ugacc!aisun1!mcovingt
   (which means "user mcovingt on machine aisun1, which can be reached through ugacc, which can be reached through psuvax"). Usenet has been supplanted by the Internet.

worldwide discussion system used daily by millions of people around the world consisting of more than 14,000 forums, called newsgroups, that cover a wide variety of interests. Usenet is available through many various computer systems, networks, or on-line services, but the bulk of traffic is transported over the Internet. Usenet encompasses government agencies, large universities, high schools, businesses of all sizes, home computers of all descriptions, and more. It is completely decentralized, and each Usenet site makes its own decisions about the set of newsgroups available to its users. It is not an advertising medium, although advertising is tolerated on some sites if it is informative and low-key.