It's not like it was some kind of closely guarded secret. The whole purpose of facebook has always been to get people to willingly submit their personal information, their location, where they go, who their friends are, what they "like" so that it could be marketed to advertisers. Advertisers love it. They get to put their ads in front of people who might actually buy their products. Like cars? Have a Mobile 1 ad and a coupon for $5.00 of when you buy a whole case! Like action movies? here is the newest trailer for that film franchise you love - etc, etc, etc. Of course it is annoying. But I remember years ago when our real mail boxes were crammed full of direct marketing. You could opt out some of the time, but most people actually signed up for more junk mail when they had a chance.