^^ You gotta get 8 people to sign up under you. There's several offers like Columbia House, etc. The easiest one is Ebay. So if you know 8 family members or friends, you can get them all to sign up, and bid on one item, and its done.
I dont know what exactly their motives are, but i'm guessing they will sell your e-mail address and possibly your mailing address. But the Mailman fucks me over with advertising already, so its no big thang to get 11 pieces of junk mail/advertising instead of 10.....