I'm playing by ear, but the one thing that stands out after reading the book is the display of karma (user / comment / post scores). One thing the book emphasizes is that if you display karma prominently, users will feel motivated to perform actions that will improve their numbers. This means perhaps going for a witty one-liner instead of a comment contrary to the community beliefs that could be downvoted into oblivion. More here:
http://buildingreputation.com/writings/reputation_wednesday/