Perhaps more people would think twice if the label for Facebook read:

Everything you say and do on Facebook will be used against you by advertisers for targeting that’s most likely to catch you at your most vulnerable, needy moment. Your consumption of the echo chamber timeline will lead to a narrower field of vision of the world. We may try to tinker with your mental well-being at any time, if we determine that a depressed state increases engagement on the A/B by any margin.
David Heinemeier Hansson – The price of monetizing schemes