It used to be a really busy forum; the General Forum used to turn over the first two pages of posts daily. There are currently a week's worth of posts on page 1 right now - they go back to October 10th. That's 7 days. Not that GS is setting records, but it says a lot about how membership declined there. It wasn't great quality all the time; some of it was just general news posts, sometimes, by wbs, or conspiracy stuff by John Kettler, who still posts, but at one time there was a lot of general interest military history/news/life stuff flying about to fill two pages a day. Just in the GF. CM:SF really zapped the place. I think the embargo on political talk slowed it down a bit, but not much. And the poor showing of the other games hasn't helped; the games that have been successful like SC or Tac Ops - their fans seem to stay in their own forums and talk about the games more (strange concept, I know). Even the CM:SF crowd seems to stay in the CM:SF forum. I think the two purges of the GF kind of showed a huge disrespect to the fans there too, and made a lot of people feel unwelcome and may have contributed to a reluctance to bother. This is all conjecture.
As one of the beta testers who at one time was active in the CM:SF forum, I know I contributed to the hostile atmosphere at one time towards critics of the game. Given how my opinion has changed towards the final product, I am certainly not proud of that period and can relate to people's feelings towards the continued tradition of beta tester conduct. But they're not all like that - some are respectful and helpful and I think there has been a trend to be more engaging. It's kind of hit or miss. The most helpful people there have been Schrullenhaft, who knows all there is to know about tech issues, and KwazyDog, who is on staff as the 3D modeller and artist who I've yet to see be anything but polite with anyone no matter how thoroughly repellent they've acted towards him in return.