How about instead of voting for ranks..we just have a list of labels you can stick on people.
And the more people choose the same label for someone decides what label they get.

1. Posts Useful Info
2. Makes Funny Comments
3. Should Be Skipped Over
4. Is Girl IRL

Ok, kidding aside.. I guess it depends on the forum if a rating system would be good or bad.
Would anyone really get any value from it? Would someone new to the boards do a search for info and only request returns by high ranked posters?
Would someone new to the boards even use the search?

In our case here, I have a feeling the rating system would be used more as a tool for punishment than anything.