Fast, high quality answers from very intelligent people. Quora's community is small and is primarily composed of people in tech/academia (probably because of i

Fast, high quality answers from very intelligent people. Quora's community is small and is primarily composed of people in tech/academia (probably because of its invite system). Real names are displayed (profiles are often linked to facebook accounts) so any response carries some weight of reputation. Every user has a timeline of new questions and recent responses that are filtered towards topics that the user follows. Presumably, the users follow topics they are knowledgeable about. So: 1. The invite system builds a small and intelligent community. 2. The filtered timeline and low volume of questions enables fast responses from users. 3. Along with #1, the addition of reputation yields high quality answers. The topic following system gets questions in front of "experts" efficiently. 4. There is a voting system for responses much like stackoverflow. Quora reminds me of HN + Facebook profiles + Stackoverflow.