A few months ago I had dinner with an old acquaintance who had moved over to the google, and I realized their new motto is "All your attentions is belonging to the google."
I don't think it was in the original business plan to go evil, but it's just the way the game is played in America these days. In brief, the rules of the game are laws written by the most cheaply bribed politicians working for the greediest and least ethical businessman, and to heck with the rest of the businesspeople, the ones who just want to play fairly in accord with the rules. Much more profitable to rig the game.
Facebook is a different can of evil worms, and I think the evil was right there in their original business plan, or at least between the lines. The problem is that most people have so little understanding of real freedom. My current joke on that topic is this equation:
Freedom = (Meaningful + Unconstrained) Choice Beer
It isn't just your negative data that takes away your freedom. Of course you can be blackmailed pretty directly with secret knowledge of your mistakes and such. It's also your tastes, strengths, and even your virtues that can be used to manipulate you, but that's twistier because you just think you're doing what you want to do--until they yank your leash.