Several people posted recently in a thread on women, mostly espousing feminist views - only to find that someone had declined to respond to their post, but instead browsed their history and downvoted every single comment or article they had ever posted.
I have two questions:
1. Why would you come to a site like this and pollute the karma system? How does it make you smarter? How does it make anyone else on the site smarter?
2. What would be a good technical workaround? In my mind, some system that detects mass-downvoting and flags a user for review would be preferable, but what should happen then? Should the system be more lenient to higher-karma posters? Who should perform the review process? What should be done with those whom the reviewer ascertains are abusing the karma system? I would prefer some kind of lesson that is more corrective than retributive - it seems to me that people who would perform this behavior are exactly the sort of people who need some of the lessons that this site provides. Any ideas?
I think the system on stackoverflow.com works well. There, making a downvote on somelne else costs you something in your vote total, whereas upvotes are free. The result is that genuinely wrong answers get a few net downvotes, presumably from very high karma individuals who don't mind the expense, and who also are presumably a good choice for "arbiter" type roles given their very high karma. stackoverflow.com karma system is pretty detailed, with priveleges and permissions coming at higher and higher personal karma levels, but I would say "charging" for downvotes is the most relevant feature for the most improvement here on lesswrong.com.
Currently there is (as far as I know) a downvoting limit of 4x your total karma, which seems to serve the same purpose. It's possible, of course, that this limit needs to be lower. But if, say, the limit were half your total karma, then it wouldn't change much to additionally charge karma for downvotes: all karma would remain the same to within a factor of 2.
Of course, charging karma for downvotes would probably also discourage downvoting, because people don't like their numbers going down. I'm not sure if this is a good thing, though; incentives mainly work well for people who are already using the system as intended, so this would discourage legitimate downvoting while leaving retributive downvoting alone.