You can find the referral information in your Financials tab on your profile page. You get a one-time payment. They also do a lot of investigating to prevent misuse of the system. For instance, I helped one of my clients sign up on my computer while they were in my office one day. Because the registration IP address was the same as the referrer, despite the fact that they've spent hundreds of dollars (perhaps thousands) in their own account, I received no credit for it. I can't say that I agree with their assertion that I set up this bogus account in order to earn 10 bucks.
