I think yes...but profitable in different ways for different people. For newbies, posting on the likes of VNWR or TNB will teach them how to successfully make money in this business far quicker than battling it alone will do.
For sponsor programs, content providers, coders, etc etc, there is definitely some value purely in name recognition. I couldn't count how many times I heard, and said, in Vegas, 'wow, I know you from xyz board'.
Naturally, posting alone won't do it, but if you can spare a little time each day/week/whatever, it sure can't hurt.
