The only other forum I post on that is sort of dedicated to an author is at:
http://forums.johnsteakley.com/
We don't really post much about Steakley or his books, since he has only written two -- but most really do like those two novels a lot. A lot of us have become friends and travel once a year to Dallas to see one another. Until last year, Steakley always came to visit, too (he was unable to attend last year) -- and we always took him and another major author out to a dinner at a pretty nice restaurant. FPW went with us once.
The posts are actually very similar to the types of things we discuss here. Movies, books, video games, politics, current events, guns, and so on. We are generally a little more polite to one another, though, and that may be because many of the regulars have met each other face to face and had some beers together. But sometimes things do get a little testy, too.
I do post on a couple of business forums regularly, mostly about search engine stuff within a certain sector of the web, but I can't imagine anyone here would be much interested in that unless they are involved in the real estate world.