The recent implementation of a -5 karma penalty for replying to comments that are at -3 or below has clearly met with some disagreement and controversy. See http://lesswrong.com/r/discussion/lw/eb9/meta_karma_for_last_30_days/7aon . However, at the same time, it seems that Eliezer's observation that trolling and related problems have over time gotten worse here may be correct. It may be that this an inevitable consequence of growth, but it may be that it can be handled or reduced with some solution or set of solutions. I'm starting this discussion thread for people to propose possible solutions. To minimize anchoring bias and related problems, I'm not going to include my ideas in this header but in a comment below. People should think about the problem before reading proposed solutions (again to minimize anchoring issues).
I didn't originally propose this for LW in general, but a different forum or section. People can earn their LW karma elsewhere. But let us for the sake of this exchange suppose here we make this a general rule. I actually like it much more than what I had in mind at first!
It should be emphasised the reverse of what you describe is constantly happening. It is easier and easier to amass 1000 karma as LessWrong grows. Comparing older to newer articles shows clear evidence of ongoing karma inflation.
There aren't that few people with karma over 1000, I'd guesstimate there are at least 100 of them. Many of those are currently active. But again making it harder to get over 1000 karma in order to vote might be a good think. A key feature of the Eternal September problem is that when you have newcomers of a community interacting mostly with other new members old norms have a hard time taking root. And yes since users takee the karma mechanism, especially negative votes, so seriously it is a very strong kind of interaction. Putting the karma mechanism in the hands of proven members should produce better poster quality. It somewhat alleviates the problems of rapid growth.
It also further subsidizes the creation of new articles. Recall your karma from writing a Main Article is boosted 10 fold.
It especially control how easy it is to post to main. 20 karma from +1000 people is worth way more than 20 random karma.