In sense 1, `network' is often abbreviated to `net'. "Are
you on the net?" is a frequent question when hackers first meet
face to face, and "See you on the net!" is a frequent goodbye.
Among the best-known are comp.lang.c (the C-language forum),
comp.arch (on computer architectures), comp.unix.wizards
(for UNIX wizards), rec.arts.sf-lovers (for science-fiction
fans), and talk.politics.misc (miscellaneous political
discussions and flamage).
There is a mainstream variant of this myth involving a `Trunk Line
Monitor', which supposedly used speech recognition to extract words
from telephone trunks. This one was making the rounds in the
late 1970s, spread by people who had no idea of then-current
technology or the storage, signal-processing, or speech recognition
needs of such a project. On the basis of mass-storage costs alone
it would have been cheaper to hire 50 high-school students and just
let them listen in. Speech-recognition technology can't do this
job even now (1993), and almost certainly won't in this millennium,
either. The peak of silliness came with a letter to an alternative
paper in New Haven, Connecticut, laying out the factoids of this
Big Brotherly affair. The letter writer then revealed his actual
agenda by offering --- at an amazing low price, just this once, we
take VISA and MasterCard --- a scrambler guaranteed to daunt the
Trunk Trawler and presumably allowing the would-be Baader-Meinhof
gangs of the world to get on with their business.