Usenet

thumb|upright=1.3|A 2004 discussion in the Usenet group comp.text.tex thumb|A diagram of Usenet servers and clients. The coloured dots on the servers represent the newsgroups they carry. Coloured arrows between servers indicate newsgroup content exchanges (news feeds). Arrows between clients and servers indicate that a user is subscribed to a certain newsgroup and reads or submits articles there.Notably, clients never connect with each other, but still have access to each other's posts even when they also never connect to the same server.

Usenet (), a portmanteau of '''User's Network', is a worldwide distributed discussion system available on computers. It was developed from the general-purpose Unix-to-Unix Copy (UUCP) dial-up network architecture. Tom Truscott and Jim Ellis conceived the idea in 1979, and it was established in 1980. Users read and post messages (called articles or posts, and collectively termed news'') to one or more topic categories, known as newsgroups. Usenet resembles a bulletin board system (BBS) in many respects and is the precursor to the Internet forums that were developed after the introduction of the World Wide Web. Discussions are threaded, as with web forums and BBSes, though posts are stored on the server sequentially.