In the unlikely event that anyone pokes around here, I include this graph of DALnet users and channels over the years.
At the current time (November, 2009), netsplit.de reports that EFnet has about 50,000 users and Undernet has around 75,000. DALnet has 25,000. When usage first dropped, the channel was often left with just two or three participants. We slowly built that up to about ten regulars, then everything collapsed again. It never recovered.
In part the reason was the instability of DALnet itself, which was beseiged by some internet miscreant[s] who brought it down over and over, frustrating users. This had a cascading effect, because users showing up to a dead channel simply went elsewhere. But most fundamentally, people seemed to find other ways to communicate. At first the culprit was said to be gay.c0m. Then the various other social sites began. I watched other gay channels decline too. Undernet's "gaycollegeboys" declined from around 50 users to 5 or so. Ditto gayteensex, once immensely popular, and almost all the EFnet gay channels.
revised: 2009-11-06