Before the credits were set to default and mostly reflected how many posts you had. The more posts you had the more credits you had.
Now post count is no longer considered that important. We are still tweaking the credit system. Once finalized I will post up what each action is worth.
i.e rating a thread, referring a member, creating a poll, Giving rep ect...
What can these credits be used for? Something good
In the future there will be contests, I'm also toying with the idea of exchanging it for money, downloads, advertising.