USENET: Internet news Software, Security - Needs and Goals
Usenet is a distributed bulletin board system, built as a logical network on top of other networks and connections. By design, messages resemble standard Internet electronic mail messages as defined in RFC822. The Usenet message format is described in RFC1036. This defines some additional headers. It also limits the values of some of the standard headers as well as giving some of them special semantics. Newsgroups are the classification system of Usenet. The required Newsgroups header specifies where a message, or article, should be filed upon reception.