That creep Zuckerberg must be laughing his ass off. He could not have bought such a dumb move to help keep users on F_c_book.
"A method is described for tracking information about the activities of users of a social networking system while on another domain." – Facebook Patent application dated September 22, 2011
Creeps and liars.
Google must be shooting for just sincerely creepy. Competitive advantage there.