This is written with highly self-reflective math geeks as the target audience. The first inclination of normal people would be to run away.
Is that a bug or a feature?
Bug, definitely. Why would you even ask that? Even if normal people can't contribute, we would definitely like everyone to think more clearly.
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."