I basically agree with this post, with some exceptions like:

My strong suspicion is that the best way to reduce existential risk is to build (non-nanotech) self-replicating robots using existing technology and online ordering of materials

But for the moment I will keep reading LessWrong sometimes. This is because of useful guides like "Lifestyle interventions to increase longevity" and "Political Skills which Increase Income" and also that the advice I've gotten has often been better than on Quora. And I do like the high quality evidence-based discussion of charitable/social interventions.