Definition - What does USENET mean?
Usenet is a worldwide system for Internet discussion that consists of a set of newsgroups that are organized by subject. Users post articles or messages to these newsgroups. The articles are then broadcast to other computer systems, most of which now connect via the Internet. Usenet was conceived in 1979, making it one of the oldest network communications systems still in use today. It is also the predecessor of many of the forums online today.
Techopedia explains USENET
Usenet got its name from Unix-to-Unix Copy (UUCP), a protocol suite for sending data, usually over a dial-up network. Initially, this was the dominant mode of transmission for Usenet, but it has since come to rely on the Internet.
Some newsgroups are moderated, which means that posts are sent to a moderator for approval before being distributed to the group. Usenet users exchange articles by tagging them with universally recognized labels. Many Internet service providers and Internet sites provide news servers, which allow their users to handle Usenet articles. Although Usenet is still used, it has become less important in the face of online forums, blogs and mailing lists.