User Network (n)~ A worldwide network of UNIX systems that has a decentralized administration and is used as a bulletin board system by special-interest discussion groups. Usenet which is considered part of the Internet (although Usenet predates it) is comprised of thousands of newsgroups each devoted to a particular topic. Users can post messages and read messages from others in these newsgroups in a manner similar to users on dial-in BBSs. Usenet was originally implemented using UUCP (UNIX-to-UNIX Copy) software and telephone connections; that method remains important although more modern methods such as NNTP and network connections are more commonly used.