Good idea. I think it is only a matter of time to see lots and lots of websites based on this concept.
Quora has a solid and working Q&A system at the moment but it is not related to crypto currencies at all. On that site, the better your answer is, the more upvotes+views you get and you can put links into your posts. So more traffic on your answers means more traffic to your sites and more money to you. It needs a little tweak and a solid algorithm to morph into something like you imagined. It could definitely work!
I'm a giant on Quora but I wish I could earn sbd there.