Google Groups 2 beta has stats on each newsgroup.

uk.telecom.mobile's stats are here:
http://groups-beta.google.com/group/uk.telecom.mobile/about

Steve Terry, under various guises, is all-time number 1 poster of
uk.telecom.mobile, with 15,758 posts to date!  Phew.

A distant second is Michael Rodgers with a "mere" 7,909 posts.

Of course people change their email addresses from time-to-time so
these stats may not be entirely accurate.

Google Groups 2 beta has some interesting new features too, presumably
culled from GMail.  Has Atom feeds too.  Definitely worth checking
out.