The more questions and answers we get, the more useful Quora is.

Questions and answers is a big space, and there are lots of possible systems that you can create for different goals.

On Quora, you're not answering questions because you want to get points or because you have nothing else to do.

A lot of people really like to answer questions, and they really enjoy sharing their knowledge. Especially people who have valuable knowledge.

I think a lot of what the iPad app is going to be used for is just reading the best content on Quora. It really helps the whole system run because people who are writing answers can get this very wide distribution to a large audience of readers.

When you look at Yahoo Answers, there can be a lot of garbage. But if you're careful about the rules and supporting good contributions, over time you can get better and better, like Wikipedia.