It's a lot harder to target specific people that like forums so most of the time the advertisements will be shown at people not interestedFacebook users don't like forums,huh?
It's difficult to say whether they'd join or not. Perhaps, the charismatic posting of several people on here would be appealing. On the other hand, it's a more difficult thing to make on my forums, but I do have one guy who is more knowledgeable on musical instruments, the topic of many of them. Possibly two or three of them would make a powerhouse.