Datamining as the New Advertising

Actually the title is a bit misleading, datamining is not something that replaces advertising, the two are complementary. But while broadcast media operated on a tacit agreement between the producer and audience that the content would be free in exchange for the audience being exposed to ads, it looks like a new tacit agreement is emerging online, the content is free in exchange for the data to mine. Its been slowly cooking for years, cookies being the first real milestone, and like in broadcast no one is rushing to make clear to the audience/users just exactly they are getting themselves into...