Other issues impact on the decline of newsgroups, but I've also seen
instances of someone setting up a highly specific "yahoo group" for one
very specific element of a larger field, and that does take that traffic
away from the more general newsgroup. But the loss is greater than the
loss of just those specific topic messages, the general newsgroup loses
those people often, they don't participate in the larger group. And in
one case I'm very much thinking of, a few years later the yahoo group is
completely dead.