For one, if you want to see the later answers, you need to log-in. On SO you can just see everything, and it used to be that you could post a question as a gues

For one, if you want to see the later answers, you need to log-in. On SO you can just see everything, and it used to be that you could post a question as a guest. In addition, there is a whole family of sites on StackExchange, each with their own set of active users and people. To me, Quora just seems like a better version of Yahoo answers, while SO is what I want a successful Q&A community to be.