Usenet is a world-wide distributed discussion system. It consists
of a set of "newsgroups" with names that are classified
hierarchically by subject. "Articles" or "messages"
are "posted" to these newsgroups by people on computers
with the appropriate software -- these articles are then broadcast
to other interconnected computer systems via a wide variety
of networks. Some newsgroups are "moderated"; in
these newsgroups, the articles are first sent to a moderator
for approval before appearing in the newsgroup. Usenet is
available on a wide variety of computer systems and networks,
but the bulk of modern Usenet traffic is transported over
either the Internet or UUCP.