A world-wide distributed discussion system consisting of newsgroups classified hierarchically by subject.
"During the early days of online communication, many enthusiasts used Usenet to participate in hierarchical newsgroups dedicated to their specialized interests."
The word USERNET is formed by combining USERS and NET to describe an online discussion network for people who use the Unix operating system. It was created specifically within the community of programmers associated with USENIX in the early days of computer networking.