Fair enough: I did work there, though never on ads, and it's been a few years. To be clear, I realize the privacy tradeoffs are probably unacceptable and I'm n

Fair enough: I did work there, though never on ads, and it's been a few years. To be clear, I realize the privacy tradeoffs are probably unacceptable and I'm not seriously proposing the FB panopticon. But I do think it's an interesting thought experiment to consider how good this could be without constraints.