“Privacy Fix”:https://www.privacyfix.com/start is instructive. Who knows how accurate it is, but I bet it is directionally correct. And it says that FB makes about 5 cents a year off ads delivered to me, whereas GOOG makes about $32. I have most of my privacy settings cranked up (on both GOOG and FB), so maybe FB does a lot better with other people, but that is a factor of a 1000.
And when you consider that GOOG has other emergent revenue streams (mobile, enterprise), well I am surprised the gap in valuation isn’t even greater.
I’d love to see more features from Privacy Fix. Who exactly is paying GOOG $32? When I visit a particular page, say SI.COM, who is paying for my eyeballs there? WHat exactly does GOOG know about me and are they telling people about me?