Quora will be successful if they can devise an algorithm which does personalized ranking of users and answers. Rank users globally, yes, but also incorporate yo

Quora will be successful if they can devise an algorithm which does personalized ranking of users and answers. Rank users globally, yes, but also incorporate your upvotes, searches, and page views as features in a correction term to locally rerank for logged in users. This way you see the answers at the top which are valuable to you specifically, ranked in order of your probability of upvote. The basic math here has been around since Kaltix in 2003. It will need to be tuned for this specific app, but an off the shelf version will be a qualitative leap over Yahoo or Goog answers. Because unlike Yahoo or Google Answers, Quora has the social graph as a critical piece of ranking infrastructure. That is a huge difference, comparable to search before and after the web, because the credibility of many nontechnical answers depends fundamentally on the identity of the respondents. And unlike Facebook Questions, they have the benefit of complete focus on one area (Q&A).