Usenet /yoos'net/ or /yooz'net/ n. [from `Users' Network'; the original
   spelling was USENET, but the mixed-case form is now widely preferred] A
   distributed {bboard} (bulletin board) system supported mainly by Unix
   machines. Originally implemented in 1979-1980 by Steve Bellovin, Jim
   Ellis, Tom Truscott, and Steve Daniel at Duke University, it has swiftly
   grown to become international in scope and is now probably the largest
   decentralized information utility in existence. As of early 1996, it
   hosts over 10,000 {newsgroup}s and an average of over 500 megabytes (the
   equivalent of several thousand paper pages) of new technical articles,
   news, discussion, chatter, and {flamage} every day (and that leaves out
   the graphics...).

   By the year the Internet hit the mainstream (1994) the original UUCP
   transport for Usenet was fading out of use (see {UUCPNET}) - almost all
   Usenet connections were over Internet links. A lot of newbies and
   journalists began to refer to "Internet newsgroups" as though Usenet was
   and always had been just another Internet service. This ignorance
   greatly annoys experienced Usenetters.


Source: The Jargon File

USENET
     USErs' NETwork (Internet)
     
     
Source: Virtual Entity of Relevant Acronyms