[fookyong]

My mind boggles at Quora too. I just don't get how they can even think of launching while Facebook are about to roll out their own Q&A feature.

The StackOverflow folks have the right idea - I think the market can support a bunch of niche Q&A sites with tight communities.

For monolithic Q&A sites on every topic under the sun, you need massive traction otherwise you have the usual chicken/egg UGC problems that we've seen a million times before. Facebook already has massive traction, Quora doesn't. Game over.

[qq66]

Q&A sites don't need a lot of users to be effective. Any group of 500 people can probably answer a question that you have, unless it's very arcane. User engagement is much more important.