More types of flagging? 
coffeemug: Gamedev.net has one of the most civil and informative forums on the internet. At some point they had a pretty mean spirited community too, and the owners pulled the site into one of the best sites on the internet. I spent a lot of time on these forums, and I think there are three main things that contribute to very high quality.- Non-threaded comments. I know this has been discussed to death, but I think the downside of threaded comments (fragmentation of the discussion and incentive for witty one-liners) far outweighs the benefit (having separate unrelated conversations). A non-threaded approach gives huge incentive to bring the community together into a single coherent conversation, gives the reader a great sense of a timeline (which gives further incentive to maintain an intelligent discussion), and discourages fragmentation of the discussion to a point where it isn't interesting to anyone anymore. I know this is a big change, but I would strongly encourage at least giving it a serious consideration - it can make a huge difference if done right.- Active topics - on sites like Hacker News and Reddit it's very easy to lose track of interesting discussions that are going on because top threads are tightly coupled with the top articles. We can have interesting discussions long after the article has left the front page, and an active topics page would go far towards encouraging intelligent interaction. Basically, every time an article is commented on, this article goes to the top of the list. This way I can see all active discussions at glance (including the ones I participated in), and continue interesting discussions, even though they're not on the front page.- User rating system (not article/comment system) - in real life, if I am usually a very interesting, intelligent person, and one day I suddenly act as a jerk, it can very seriously ruin my reputation. On gamedev people rate users, not comments and articles. So, I can give a user a rating - extremely helpful, helpful, not helpful, jerk. The karma is a combination of ratings for a given user, and the strength of a user's vote is proportional to his karma. So, if someone is a jerk one day, it can affect his karma far more significantly than simply downvoting his comment. In addition, jerks have less affect on the system overall. Rating people's comments never made sense to me - it always ends up signaling agreement or disagreement vs. usefulness. If people rate users instead of comments, this problem goes away always entirely, plus very strongly discourages aggressive behavior.I think these three things would help immensely to scale the community. These are big changes, but I think they're worth seriously thinking about.