Yea the idea of social media minning datas from its users been the talk on all channels recently and from analysis gathered seems they are beginning to loose their worth in terms of monetary value, the above remind me of a speech a steemian made one day, that's he was scrolling through his feed and for some reason a ads popped up about wine glass and the funniest part he was actually discussing about it some few mins back, just goes to show that the data mining is real and all messages typed online be it personal or public is no longer safe/secure.
Unlike steemit which you quite know that everything you input is available to the public, on Facebook its another thing entirely.
From what I heard this morning seems the main problem is that technology is growing too fast and laws are yet to be made guiding such actions/activities