Need 10,000 - 1,000,000 Opt In users for stock trading websites (no overlap in users!)

I have 3 stock trading community websites. Two of the sites only require the user to sign up with their email address, and have no other interaction from the users. I would like to get between 10,000 and 1,000,000 members signed up on each site, and they must be legitamate people, whom signup themselves, and concur with the can-spam act during this process, as well as there cannot be overlap (not much anyways) between the signups on the sites. I will test this process out on one site, then move to add members to the next site, and then the next site as well.