"Today, we are beginning to see the emergence of online knowledge marketplaces where you can sell your personal knowledge. You can see its roots in the crowd sourced Q & A trend that spawned sites like Quora, Aardvark, Stockoverflow and others. And sure, you can go to Google or Ask.com and get your questions answered for free."
-Jennifer Hicks, The Rise of the Knowledge Market, Forbes, June 27, 2011.