Get a 7 Day Park Hopper for the Price of a 4 Day Ticket

I got an e-mail from Dell inviting me to join something called Dell Perks. It piqued my interest because one of the teaser offers was for Disney World tickets. I signed up and and saw that they had an offer for a 7 day park hopper ticket for the price of a 4 day park hopper ticket to Disney World in Orlando. This is a pretty good deal. As far as I know, anybody can sign up for Dell Perks. Here is the link.