So they built a tool that did the technical work of turning special access on and off and also kept records on what are known internally as “capabilities” — the special privileges enabling companies to obtain data, in some cases without asking permission.
The Times reviewed more than 270 pages of reports generated by the system — records that reflect just a portion of Facebook’s wide-ranging deals. Among the revelations was that Facebook obtained data from multiple partners for a controversial friend-suggestion tool called “People You May Know.”
The feature, introduced in 2008, continues even though some Facebook users have objected to it, unsettled by its knowledge of their real-world relationships. Gizmodo and other news outlets have reported cases of the tool’s recommending friend connections between patients of the same psychiatrist, estranged family members, and a harasser and his victim.
https://www.nytimes.com/2018/12/18/technology/facebook-privacy.html