I participate in a few sites that exist to help people find answers to questions. Some software developers that I follow started a site called StackOverflow for programmers which is perhaps the #1 source of useful information for programmers. You earn points on the site for asking good questions and providing useful answers. People vote for questions and answers and you are awarded badges like in Call of Duty! They made the technology used on the site available for others to start their own Q&A areas for various topics. Only those topics that can prove themselves as legit are accepted at StackExchange.
I participate in the following sites:
The awarding of badges on these sites is a great idea and one that my new company Qliq uses for their Couponing/Social Networking smartphone app.