The point is, Google isn't just "selling space." They collect the data about you, admitting themselves that they prefer to never delete anything. The key word is "targeting," remember? In process, they still know more about you than your mother or partner. Somewhere in their guts, there is a collection of data about you, the depth of it not even imaginable before.
How we got here: Moxie Marlinspike, 2010: