Facebook does what it can to underplay how much data it gathers through contacts, and how widely it casts its net. “People You May Know suggestions may be based on contact information we receive from people and their friends,” Facebook spokesperson Matt Steinfeld wrote in an email. “Sometimes this means that a friend or someone you know might upload contact information—like an email address or phone number—that we associate with you. This and other signals from you help us to make sure that the people we su