Alright.. I would make it a paid to access forum, even $5 to access it Or make the BST section paid like Sitepoint. Would eliminate a lot of crap and show real sellers.
Obviously not all are active. It would probably be around: 400x5=$2000 2000x5=$10000 Once again, just a rough guess.
If i own dp, I would not sell dp right away. I would do it like some of you guys said: I would make a section, where the members of the forums would have to pay only 1$ per month to enter it. And then i would have fun and be happy, because of owning such a big, used forum with so much income of adsense revenue etc.
Thats a wise move if u acquire $1 per month people demanding for more will probably make people loose their interest in dp as it will be so very expensive.
It's not like every member including inactive and banned would come back each month to buy the subscription..