I think there should be a "cost" to downvote; it's like throwing stones -- there's a social inhibition against doing it, until someone starts, and then all of a sudden, WHAM, viral release of anger. There's some really interesting epiphenomena about the voting system on SO. I've noticed that there seems to be several different tiers of votes:
- The highly upvoted answers. These have several advantages: they're usually good answers (have merit), people see the vote counts so they're more likely to reinforce that, and they show up first on the "votes" tab so if you're looking at that, and there are a lot of answers, you see them first.
- The answers that have a net vote count of 1 or 2. Someone's already voted them up, so it's socially more acceptible to reinforce that vote. If there are only a small number of answers, you'll notice these, but if a question has 10 or 20 answers, they tend to get lost in the shuffle.
- The answers that have a net vote count of 0. I think people are hesitant sometimes to upvote or downvote something that has a 0 vote count... you really have to read an answer and judge it on its own merits. For a question with lots of answers, these tend to be down towards the bottom and get read less frequently.
- The answers that have a negative vote count. Again, it's easier to vote down someone who's already been voted down. These are at the bottom of the list and are read less frequently.
I personally don't care much about the reputation score, the only advantages to me are being able to have some editor abilities, and to be able to offer some of it as a bounty. I do care about the social aspects of Q & A voting. This site has several advantages over newsgroups, one of them is that people here tend to be more helpful and less sarcastic. I'd like to see that continue.