The sample size is small so far. I can't think of a lot of sites that have tried really hard to avoid becoming lame, even at the expense of growth. Most put growth first.
Less than it would with other people. I get a lot of info about which forums exist from referring urls. That was how I learned about both Delicious and StumbleUpon. So I can at least say with fair certainty that there's no good smaller forum where people link to my stuff. Except here of course.
Metafilter might count as an exception. They often have interestesting links. But reading the comments is like eavesdropping on a bunch of freshmen at Oberlin.
TechMeme is not bad, but I don't think the sites they link to are decided by user votes.
I'm sure there are thousands, for everything from hydroponic gardening to fursuits. I wasn't saying there aren't good small communities, just that there aren't any except News.YC in the subset of the world that reads the kind of thing I write.
The sample size is small so far. I can't think of a lot of sites that have tried really hard to avoid becoming lame, even at the expense of growth. Most put growth first.