I think the community does a great job policing questions/answers, etc. and the community has some good tools available to do this. Between flagging questions with some reasons behind it and editing posts, closing them, and deleting them, the only thing that seems to be missing to me is the ability to flag a user.
Reasons to flag a user as abusive:
- Duplicate User
- Abusive Behavior
- Offensive user name or profile
- User profile consists of spam