"John Byrns" wrote...
Or perhaps it is simply due to the
proliferation of groups, with both usenet and the "forums", sharing a
limited number of posters so that there are less posters available to
each group irrespective of whether it is an um moderated usenet group or
an older moderated "forum".

That's my guess. More places to talk, and fewer people talking in any
particular group.

Imagine a small town that originally had one tavern. Two new taverns open up
as the town slowly grows (or maybe doesn't grow at all).

Newcomers find some place where they feel comfortable. Some will stay and
others will move on.

Oldtimers may stick with the original, or spread out and find a new place
they like better . . . or just make the rounds once in a while.

Regards,

Phil Nelson