I've been having a perplexing issue with the down-voting feature on SO lately.
When somebody down-votes my answers, I'd really like to know something about the user who down-voted me. It's certainly not because I have a grudge against the other user. Quite the opposite, I'd like a little insight to if it's somebody who has a high reputation (and thus a little more weight when it comes to their opinions).
Obviously, there's no good way to show exactly which user down-voted an answer without starting a flame war. My only other reasonable thought was to weight the down-vote. It's quite simple in concept:
A User with a high reputation downvoting your answer = More points deducted
It could easily be done in steps based on Rep:
1 - 5000 = -2 Rep 5001 - 10000 = -3 Rep 10001 - 15000 = -4 Rep
...and so on. That way, when you see the decrease you at least know the range of the user that downvoted you and then can (theoretically) see if there's something seriously flawed in the answer (which requires fixing/deleting) or simply a user mis-understanding part of the answer.
I understand that this isn't perfect logic but, in my opinion, it's better than not knowing anything about who downvoted you (or why).