StingingVelvet: The whole point of the site is sharing your info, and you only share what you want. Also obviously the business model of the site relies on your data being given over. That's what all that "I agree" stuff means kids!
That is blatantly and provably false:
https://gizmodo.com/how-facebook-figures-out-everyone-youve-ever-met-1819822691 Not only that, I'm pretty sure neither you nor your wife are actually fully cognizant of the extent of Facebook's data acquisition. Your using their site is not the only input method - they also have access to your purchase history via third-party credit card information, any governmental "open records", and may or may not be able to tap into actually restricted government databases (the extent of overlap between Facebook and TLAs is something I do not expect to be raised during the incoming Congressional deposition of Zuckeberg).
https://www.washingtonpost.com/news/the-intersect/wp/2016/08/19/98-personal-data-points-that-facebook-uses-to-target-ads-to-you/
https://techcrunch.com/2018/01/23/facebook-confirm-io/
The whole uproar about CA and Facebook is not so much about the fact that they gather and disseminate private information, but the realization of just how dangerous such practices can be to democratic systems.
Something that has been getting me labeled as "paranoid conspiracy theory tin-foil hatter" since I started discussing such topics in early 2000s.
The sad part of the situation is that most likely the general apathy due to lack of understanding of the subject will lead to pretty much nothing (at least in the US) changing, just like it happened with Snowden's revelations of mass unconstitutional government surveillance of US population (also something that was laughed out using the usual epithets since techies started pointing out the practice a decade or so before Snowden).
For crying out loud, socials are already mined in the US by insurance companies, among others (and for a while, too:
https://www.cnbc.com/2014/04/16/data-mining-is-now-used-to-set-insurance-rates-critics-cry-fowl.html). Do we really need to wait until companies "individualize" prices of products based on compiled user profiles (much less end up with a sociopathic cleptomaniac as a president) before the society as a whole realizes that technological capacity for certain things does not make them beneficial in the long run?
The power of mass population surveillance, whether government-controlled or, even worse, concentrated in hands of profit-oriented megacorps, is one of such things.