I sometimes downvote things that seem mistaken. I think most users do. This didn't use to be a problem when there were only a couple thousand users who often knew one another personally. The problem is voting to agree/disagree combined with a larger and probably less thoughtful audience. That's when it starts to feel like a mob.
Using downvotes as a way of expressing disagreement is, I believe, unfair to a commenter if he/she is courteously stating his/her point of view or idea, mainly because downvoting inflicts a penalty on the user's karma - which many users, I surmise, care about.
I don't think users should be penalized for siding with one aspect of an discussion just because other users disagree and proceed to downvote based on their own personal opinion. It's not even the best way of determining majority (which I believe is, partly, the purpose of the system), since not every user makes use of the feature.
Some sort of hybrid might be the most comprehensive solution. Probably something along the lines of upvotes raise karma (compensating good input), downvotes don't affect karma (their purpose becomes, then, to provide insight on the general opinion of a subject), and flags affect karma negatively for rude or uncivilized comments.
Strictly speaking a vote does affect someone's karma. But it doesn't cause their karma to be net decreased as a result of posting a comment unless you downvote the comment below 1, which most people don't do lightly. I think of the up and downvoting as a collaboration to determine how much additional karma someone should get for posting a new comment.
Regardless, the fact the downvoting is just as easy as upvoting (and has no undo) strikes me as odd.
I suggest downvoting cost the voter something, not just the votee. 1:1 seems simple enough. It would also give greater pause to newer users than veterans. However, an undo (perhaps timed like comment editing) would be more desirable in this case.
So the original purpose of binding comment scores to karma was to _supplement_ the overall karma of a user? Not to be confounded as one of the core ideas behind the whole system?
Regardless of the original purpose, I think that fomenting conversation should be one of the most prominent ideas behind the whole karma deal. The comments and the conversations are what make HN different (and, of course, demographics, which consequently means that the comments of this given demographic, self-targeted, is what makes HN great), and I know many concur with that statement.
My voting behavior is pretty closely related to the comment score: if I think the score is "right", I usually leave it alone, but if it's too high I'll downvote for disagreement. I think there's a big difference downvoting a comment at >2 and downvoting a comment at 1 or below.
I also routinely upvote comments I disagree with but find well-reasoned nonetheless. Especially if they are unusually difficult for me to refute.
There is clear statistical evidence that many (perhaps most) users view scores this way. On the whole that is probably good, because it tends to prevent scores from going to extremes in either direction.
I wonder if there's a statistical test for mob voting... a mob vote is a vote reinforcing an already extreme score, a mob voter is someone whose votes are usually mob votes?
