The more direct response to the OP would be to limit downvoting based on whether a user has already downvoted another post of the same user already. But even that gets silly.
890 karma · joined June 5, 2009
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(Blatantly copied from http://news.ycombinator.com/item?id=659520)
Unfortunately, I think I was unable to find the first of those links, so I re-submitted the website.
Thanks for the comment.
Off course, there are probably problems with this, too.
[1] http://www.nytimes.com/interactive/2009/02/13/nyregion/Buffa...