Facebook’s People You May Know feature suggests friends based on mutual friends, work and education information, networks you’re part of, contacts youve imported and many other factors. Fusion editor Kashmir Hill published an interview with a father who attended a gathering for suicidal teens. The only thing the two people seemed to have in common was that theyd been to the same meeting. Facebook first suggested that location data was used, then said that it wasnt used at all, then finally admitted that it had been used in a test late last year.”]
Source: https://nakedsecurity.sophos.com/2016/08/30/is-facebooks-people-you-may-know-putting-users-at-risk/