Facebook faced a lot of criticism for it's privacy issues - and many alleged them to gather data to make us totally transparent. I don't think even the best algorithms these days can actually describe us by what we do on Facebook. Or let;'s say, they maybe can do, but there is no reason for Facebook to use it, if so.
These are the people Facebook suggested to like me:
If this wasn't a "dumb" machine, it would have know that it doesn't make sense to suggest me both leaders of opposite political parties. It wouldn't suggest me a random singer. It is only suggesting it because some people I know like them, and that's enough for Facebook. It's currency is likes and engagements, and popular people likely create more likes and engagement than some niche groups or pages.
So, I am not so much concerned about what Facebook and Google do with my data. I am concerned what governments do. They are the threat. Still.