I know I'm new here, but I'll give you my 1/50th of a dollar on it. The best management I've seen was a system where there were 3 levels of access.
Level 1 was for newbies and lurkers only. These threads would be for things that the board and site were specifically set up for, and here I'm guessing it would be the Market Outlook, individual Account talks, etc.
Level 2 could be reached after you had posted a certain number of times and held threads on religion, politics, and other potentially flamatory topics. In the case I mention the number was 50 posts in good standing, meaning, that in the opinion of the moderators the individual had behaved well enough to be rewarded with increased access. In this way we were able to have lively discussions while at the same time protecting our reputation (such as it was) a little in the public eye. Having Level 2 was also a useful tool for behavior correction. Instead of having only the Ban Hammer to punish somebody, somebody could be Whiffle Batted back to Level 1 until they had earned their Level 2 privleges again.
Level 3 was reserved for the paying members. Level 2 permissions was a useful temporary banishment area for Level 3 miscreants who need to be Whiffle Batted back into line a bit. That said, however, I think that Whiffle Batting any Level 3s here back to Level 2 wouldn't be right as many Level 3s probably use the information in those threads to base financial decisions, so I would hesitate before utilizing that method here.