yea..the sad thing is..if you look through the TOS or whatever I'm sure you'll find some sleazy junk in it about you have to accept being put on their e-mail list and junk like that.
No one does anything for free. Just remember that. Either they have it all worked out to where it'll bring in a ton of advertisement bucks or their partners will pay them for it (like this case, accepting offers and e-mail mailing list and junk).