See this is the problem (not you campbell i know you're just running an experiment). People hear about this from thier friends, so they ask everyone they know to sign up as a referral. Well there are only so many people you know and have acess to, so eventually people have to resort to spamming message boards, chat rooms etc to find refferrals. It's just another version of a MLM program. If you can find external refferals (other than people you know), then there are plenty of ways to make real money.

http://en.wikipedia.org/wiki/Multi-level_marketing