I agree with Jamison. I've learned that when you buy e-mail addresses, you have no more guarantee that some will sign up to your program than if you put your site on a traffic exchange. The best way to go is marketing for qualified leads. Purchased e-mail leads may work, then again they may not, but if you have a person that is truly interested in what you are doing, rather than someone who just saw your site, you have a better success rate.