Recently there has been created a new About page, and a short Tour for new users on Stack Exchange, which is really the solution for this feature request.
I think this is great, but there was one thing I was a bit surprised about regarding the focus on how to gain reputation:
Your reputation score goes up when others vote up your questions, answers and edits.
Here is mentioned that you get +2 for edit approved. For new users, I think instead, it would be more important to emphasize that you get points for accepting an answer to your question.