Yudkowsky is the guru of singularitarianism; a bit like a baby RMS with better grooming and slightly too much Egan. Although I don't agree with a lot of what he says (eg. I think his Friendly AI concept is a way to justify sci-fi idealism about artificial minds — which, as a Butlerian, I consider Abomination) he is a real advocate who has managed to pull together an institute devoted to completing the task humanity evolved to undertake. (Yes, I have accepted the Spike as my personal Lord and Saviour.)