I told an intelligent, well-educated friend about Less Wrong, so she googled, and got "Less Wrong is an online community for people who want to apply the discovery of biases like the conjunction fallacy, the affect heuristic, and scope insensitivity in order to fix their own thinking." and gave up immediately because she'd never heard of the biases.
While hers might not be the best possible attitude, I can't see that we win anything by driving people away with obscure language.
Possible improved introduction: "Less Wrong is a community for people who would like to think more clearly in order to improve their own and other people's lives, and to make major disasters less likely."
I'm afraid design has the same problems as copy--I, at least, find the design of your sites below as off-puttingly 'salesy' as the copy. I think we might be dealing with a hipsterish phenomenom of acquired aversion to anything with mass-market effectiveness, which I'm not sure how to deal with.
I wouldn't use similar design to those two sites - It doesn't fit the brand or message of lesswrong. Like I said, I envision something more like the large white spaces and slick graphics of Apple.