Yeah, this is a very good idea having it the way it is, but what I think would be better than the 20 post count limit is for example, you must have been registered for 1 or 2 weeks to get access to the market section. To be honest if a legit guy wants to join the OSbot community he will be staying for more than a week or two, so it would not be such a big problem making them wait a week after joining to get access to the market section. This would get in the way off many scammers and scams. And talking about 20 posts, a guy can register and make 20 posts in a few minutes so this isn't really a big enough obsticle for them.
Anyway this is just my oppinion/idea. What do you guys think?