the whole "reputation" system is worthless.
Some people getting smacked down (logically, like being proven wrong in a post) by someone will (and do) retaliate with negative reputation, be it deserved or not.
Unless this is accounted for somehow, then the system is flawed from the get-go, and discourages negative (meaning criticizing, deserved or not) comments.
Maybe some of you want to live in a world where people pat each other on the backs all day, but I want to know what you actually think - And I want you to say it to me, not leave some negative rep that you don't have to back up.
Of course, positive reputation can be just as meaningless, regardless of attempts at "abuse" - I mean, what if a really dumb person thinks your post is the best thing since sliced bread? I guess it will all balance out over time, but it seems a situation rife with abusive possibilities, each way.