From: JeffRelf.F-M.FM on

Quoting WikiPedia:
“ UUCP networks spread quickly due to the lower costs involved,
and the ability to use existing leased lines, X.25 links
or even ARPANET connections.

By 1983, the number of UUCP hosts had grown to 550,
nearly doubling to 940 in 1984.

As the mesh of UUCP hosts rapidly expanded, it became desirable
to distinguish the Usenet subset from the overall network.

A vote was taken at the 1982 USENIX conference to choose a new name.

The name Usenet was retained,
but it was established that it only applied to news.

The name UUCPNET became the common name for the overall network. ” ―
http://en.wikipedia.org/wiki/Usenet#Network