This is also true. I don't see how they're making money off their extensive knowledge about me. When I make the mistake of buying something online in a browser

This is also true. I don't see how they're making money off their extensive knowledge about me. When I make the mistake of buying something online in a browser logged into facebook, then I get adds for a week trying to sell me what I just bought... this does not lead to me buying another one! And all this strategy seems to need is basic cookies, not a shadow profile.