Points help users to become trusted and established members and are a good indicator of user activity and quality. Also various Member Levels, Privileges And Permissions may be given to the member based on those points.
When you register and become a member you are automatically given 50 points. Each member will gain or loose points when certain action is performed.
The table below lists points gained per action:
All registered users starting out: 50 points
Posting a question: 1 point
Selecting the best answer for your question: 1 point
Posting an answer: 10 points
Having your answer selected as the best: 20 points
Per up/down vote on your answer: ±5 points
Voting up an answer: 1 point
Voting down an answer: 1 point