I suggest a new reputation. It can be just a counter of how people treat someone here. Or it can grant some additional in-game bonus (positive or negative ). Make it so that only mains can vote (for some reasons I believe that people will use lots of alts to cheat). One main can vote multiple times, but only one vote - negative or positive - to use for or against one person.
Also, new achievements can be made for both some level of positive and negative reputation.