Credit points are useful, especially on this site. They are kind of like money. You can get things for them, and you can sell things for them. For example, at Cact's Pokesav Shop you can get certain things for a certain amount of CP's. You can get 1 pokemon with any item.
Here is a list of things you can do to get CP's(This will be updated momentarily):
1. Beat the Gyms. If you beat one gym, you get 10 CP's. If you beat all the gyms, you get 80 CP's after you finish beating them. Make sure to tell an admin about you beating all gyms so they can add your points.
2. Post a useful Guide. Depending on it's quality, an admin might give you a certain number of CP's. If it sucks you get little CP's, and visa versa.
3. If you win the Signature of the Month Contest, you get 45 CP's.