Usenet (/ˈjuːznɛt/), 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.
A major difference between a BBS or web message board and Usenet is the absence of a central server and dedicated administrator or hosting provider. Usenet is distributed among a large, constantly changing set of news servers that store and forward messages to one another via "news feeds". Individual users may read messages from and post to a local (or simply preferred) news server, which can be operated by anyone, and those posts will automatically be forwarded to any other news servers peered with the local one, while the local server will receive any news its peers have that it currently lacks. This results in the automatic proliferation of content posted by any user on any server to any other user subscribed to the same newsgroups on other servers.