Quora: a Q&A Engine

Quora has been around since 2010 and has gained a solid reputation as a good community driven Q& A engine. At the end of April, they announced they had nearly doubled their monthly user base from 100 million to 195 million over the past year. 

They don’t require you to be registered to use it and have over 200 million monthly unique visitors. The platform is still relatively Unproven, however.