[tsally]

Excellent. This should help, although unfortunately such a system is only as good as the average quality of the user-base.

That's why I advocate selecting a group of trusted users to do it instead. Its non trivial to select this group correctly, but I think the end result is more effective. Over time you can expand this group based on the users that have the highest percentage of civil comments. Once you get the ball rolling, the group simply scales as the site gets larger.