Why does Experts Exchange exist? How is it different?

Experts Exchange is based on a point system. It's free to join, but you only start out with 75 free question points. In order to ask questions, you have to spend points. To earn points, you have to answer other members' questions. The more questions you answer, the more questions you can ask.

This puts a different spin on the whole community. No longer are there merely "users" trying to get free answers to tough questions, it's more like a classroom. If you are just a beginner, you can't ask questions forever, eventually, you'll have to answer some. Even if you don't have a question at the moment, you still want to check the boards to see if you can answer one.