I'm personally not sure if Quora will ever be bigger than Twitter, but I do think they have a potential advantage in the fact that user who ask questions are lo

I'm personally not sure if Quora will ever be bigger than Twitter, but I do think they have a potential advantage in the fact that user who ask questions are looking for answers when using their service. It's similar to the difference in value of search ads vs display ads. Getting an ad in front of someone who's searching for something specific is a hell of a lot more valuable than putting that same ad in front of someone while they're browsing. Most usage of Twitter is browsing, while Quora users (at least the ones asking or researching questions) seem similar to searchers, so that portion of their traffic may be much more valuable, depending on how successful they are at monetizing it. One problem with this theory is that some of Quora's traffic right now (don't know the proportion, but I'd assume it's high in terms of page views) is users answering questions or browsing updates from friends, who fit more into the browsers mold than searchers. I think they're going to have the same difficulty monetizing that portion that Twitter is.