Sex Workers: Clients Are Seeing You On Facebook, Here’s How To Stop It (2015)

There was something very similar recently as well https://news.ycombinator.com/item?id=12388370 'Facebook recommended that a psychiatrist’s patients friend each other'

Admittedly this submission is a bit weird, but I think it illustrates some of the unintended consequences of all this incredible data mining we're being told all the time isn't hurting anyone.