I am what I consider to be an "active" member. I have to admit that I'm one of the people that's talking about how slow it's gotten here. It's true that the pace here has slowed significantly, but that is to be expected when you consider the fact that the newer versions of UBB are basically maintenance releases with some added functionality that UBBDev members already had via hacks.
The one thing that sparked a lot of interest was the Portal. If you look at the original thread that started the whole thing it took off like wildfire. You have to remember though, the reason that there are 19,000+ members here is the fact that we can't code these for ourselves. Look at the ratio of givers and takers here and you'll see why UBBDev has been so popular in the past. Most of the hacks in the 6.3 Mods forum are hacks that have been ported from earlier versions. We have Allen porting hacks like mad (gotta love him for it) and we have LK writing great hacks as well but aside from that there are not very many things being written.
I have to admit that my attention has been drawn away by a CMS system that I'm adding to a couple sites that I put my heart and soul into. I'm not a talented programmer or a graphics god but I muddle through pretty well. If there was a way to allow us common folk to integrate a UBB.Classic into our web sites more easily then there would be a whole lot more activity here. The internet is in a constant state of flux, and there are projects that are making it easier for less talented people to have more and more dynamic sites, UBB.Classic isn't keeping up.