OK, I've got a few questions/observations. I notice you want to make the site for people in the industry only. I agree it's cool to have our "special club". But I'm going to play devils advocate.
1.What will you lose by discouraging participation from people not in the industry? There is a HELL of a lot of knowledge out there to be shared by people that aren’t in the industry. Do you think this forum would be the resource it is if it was "professionals only".
2.What do we gain by making it “professionals only”? I suppose we could talk about pricing a little bit more openly. And I guess we wouldn’t have to see “where can I buy such and such cheaper posts”. What else do we gain?
3.How do you intend to verify that someone is really in the industry?
4.If you limit participation to people only in the industry you will probably not get more than a few hundred members (just guessing). Won’t that limit the site from growing as well as from getting advertisers? Is making it a money making enterprise a goal?