A vote from someone counts more if the person votes seldom
Could you explain this bit? I'd expect someone who votes seldom to have lower quality votes, because ey're likely to read less of LW.
The assumption is that it is that we will capture the variable of "how well do they know lesswrong" by measuring how much they are upvoted. I think the most important part is that votes by people with high karma give more karma. The best kind of upvote is one by someone who is very very popular on lesswrong because they say lots of important stuff, but almost never thinks anything is worth upvoting.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.