I recently joined ecademy, and have found some of their forums to be helpful to my business for marketing purposes. I hestitated joining the VA forum, since I am in so many other forums (like this one

) dedicated specifically to VAs. In the end, I did end up joining, but the forum seems to be full of call centers in India than anything else.
I have joined the referrals club, the article marketing club and a few others. If nothing else, I will at least get some good ideas for my own marketing and referral network.