User-account reputation karma.
Based on the voting system that slash of had, but on the character of the account rather than the comment the account made. Here is how it works:
You have your comment up down arrows, then username, then a drop down to mark the character of the account at the time they made the post.
So you could see a comment by samstave and upvote/downvote it, and then also tag my character as [insightful|helpful|abrrasive|troll] etc (whatever the tags are you want to make)
These tags affect the overall account. So if I were tagged by a ton of people as a troll account the more troll votes I get, the worse my account experience is... And eventually too many could lead to hellban.
On the other end, having a very high positive account character would make for a better experience - see stories esrlier, be able to affect other accounts in some way etc. or just a leader board of who is the most technical, helpful, insightful, innovative etc...