Thanks for that link.

It occurred to me that Eliezer's intuitions for moderation may not be calibrated to the modern Internet, where there really is a forum for people at every level of intelligence: Yahoo Answers, Digg, Facebook, 4chan, Tagged (which is basically the smaller but profitable successor to MySpace that no one intelligent has heard of), etc. I saw the Reddit community denigrate, but Reddit was a case of the smart people having legitimately better software (and therefore better entertainment through better chosen links). Nowadays, things are more equalized and you don't pay much of a price in user experience terms for hanging out on a forum where the average intelligence is similar to yours.

Robin Hanson recently did the first ever permanent banning on Overcoming Bias, and that was for someone who was unpleasant and made too many comments, not someone who was stupid. (Not sure how often Robin deletes comments though, it does seem to happen at least a little.)

If we don't downvote, comments on average get positive karma - which makes people post them more and more.

I don't think this effect is very significant. I find it implausible that people post more comments on Hacker News, where comments are hardly ever voted down below zero, because it gets them karma. But even if they do, Hacker News is a great, thriving community. I would love it if we adopted a Hacker News-style moderation system where only users with high karma could vote down.

I like the idea of promote/agree/disagree buttons somewhat.