[dmarquis]

I think the comparison should really be between Quora and the whole Stack Exchange family of sites.

I think there are two main reasons many of the areas in Quora are useless. First, Quora never got commitment from a group of verifiable experts to answer questions in an area before opening. Its a chicken and egg problem, experts won't join if there aren't already experts. SE goes halfway there by ensuring there is a community of people to use each particular area the site before bringing it online.

Second, question askers on Quora are lazy. They don't explain what they have tried to do to learn about the answer already. They often don't know things that could have easily been found on google in a few minutes. Nobody wants to spend more than a fraction of the time on an answer than the asker has spent looking for an answer. So when an expert goes on the site they see a community of people who just want to get their knowledge without putting in any work themselves. QA sites will never replace search (as many of the Quora fans claim) for this reason.

On SO this isn't as much of a problem. First,because its very hard to find answers to programming problems with search . Second, question askers have to explain carefully what they have tried in order to expect answers. However, on some other SE sites this is just as much of a problem as on Quora.