Thanks for the feedback run4yourlives! We debated the RIAA bit for awhile, and they seem to clearly state "renting, leasing, etc.," of a CD is illegal, the theory behind the site would be we're assisting each person on the list to sell the CD to the next user (convoluted, I know, but think eBay in a strange way)
Hmm. In that case, I think you'll eventually need to reword things to say that you can buy a used cd from people, and sell your cd's online as well for fixed prices. Tricky stuff to navigate nonetheless, but it doesn't mean you shouldn't try. Good luck to you!