Quora is ranking a lot lately since it's like the academic snob version of yahoo answers.
This seems like their tactic to get more free content. Offer incentive for people to ask more questions and then the academics will answer it.
Quora is such a good idea. By discouraging the low IQ to participate by grammar policing, verifying identities and credentials, they've create a club for academics to flex their ego and intellect answering questions. Then they profit with the traffic it brings. Essentially they get expert writers and topic ideas for free and done for them automatically.