I still think all the Quora bashing about their signup interstitials is overstated. They've determined the optimal experience is for people to sign up to see an answer. I know that seems antithetical to an open and "easy-to-use" Internet, but this isn't Wikipedia. Quora is about answers but also about opinions. Their email newsletters, although tweaked recently in a not-so-favorable way, are still amazing. You get a ton of value becoming a user, but unless you sign up (or are semi-forced to sign up) you'd never know that.

While I keep saying I'm not sure if it'll be a good business, I love Quora. They've done something truly unique in the Q&A space and I'm happy they have so much funding that they'll be around for years to come regardless of whether it's a "business".