Skillpunch - A directory for online learning resources. Buzz Tracking. Smarter online research - annotate, organize & collaborate on web pages. Top 10 Ways to Find Better Answers Online (that Aren't Google) - Lifehacker. A warning about Quora: parts of it are pretty much taken over by Paleo diet... not sure what to call them, maybe 'missionaries' fits best.
Expect it in any area involving diet, exercise, health, and even some history ("Why did people in the OT live so long? "). Wikipedia's got issues, too. Startingpage Search Engine.