A couple years ago Joel Spolsky and Jeff Attword had an idea to create the Stack Exchange Network, a site where people form communities where they can contribute and/or learn. Here's how it works:
After someone asks a question, members of the community propose answers. Others vote on those answers. Very quickly, the answers with the most votes rise to the top. You don’t have to read through a lot of discussion to find the best answer.
Like topics on Wikipedia, questions and answers on Stack Exchange can be edited. If someone writes the beginning of a great answer, someone else can embellish it and make it even better.
The site is free and open to everyone. You don’t have to register, but if you do, you collect reputation points when people vote up your answers, which will appear next to your name.
There is a Bicycle Stack Exchange where you bike nerds and cycling mech heads can put your addictions to use for even greater public good. How cool is that?