And this is why under German law the BDSG §34 exists, which allows every citizen to request, once every 12 months, for free, from every company a list of all data the company has on the citizen, how they got it, whom they gave it to, and all statistical models that were derived from the data, or that had an influence on the data.

It’d be interesting to make a BDSG §34 request about "People you may know", just to see how Facebook responds (and if you have to pull them through court)