I think you underestimate how much Google knows about people. It seems to me that what you say is much less relevant to marketers than what you do, and in what

I think you underestimate how much Google knows about people. It seems to me that what you say is much less relevant to marketers than what you do, and in what you do, it's not obvious to me that Facebook has a big advantage. On Facebook, you might fill in a field saying that you are married or that you have kids of a certain age. Google knows that you have made a number of searches about diaper price, or quality, or about using cloth diapers, and have spent time on, say, price comparison web sites or parenting forums. From this kind of Google data, advertisers would know to send you adverts emphasising the price of their diapers (rather than trying to sell you high quality, expensive, diapers), and they know this with more confidence than they could extrapolate from what you say on Facebook. It's true that Facebook also has data about what you do (commenting and liking on particular updates and photos, for instance, and web traffic data from Like buttons on pages), but note that this doesn't depend, any more than Google's data depends, on the user being truthful about their own real-world identity.