Facebook launched its feature called People You May Know (PYMK) in May of 2008. The purpose was to help users build their network of friends by letting them know who else was on Facebook. The results can be spooky, when you see someone there that you know, but haven't thought about in years. That comes about from Facebook's amazing data-mining power. After all, they take control of your address book, containing emails of not only friends and family, but anyone you've emailed -ever. And you can't opt out of PYMK. People who show up in your suggestions can include your spouse's secret lover, your favorite hooker's other clients, or the person who raped you years ago.
In the summer of 2015, a psychiatrist was meeting with one of her patients, a 30-something snowboarder. He told her that he’d started getting some odd People You May Know suggestions on Facebook, people who were much older than him, many of them looking sick or infirm. He held up his phone and showed her his friend recommendations which included an older man using a walker. “Are these your patients?” he asked.
The psychiatrist was aghast because she recognized some of the people. She wasn’t friends with her patients on Facebook, and in fact barely used it, but Facebook had figured out that she was a link between this group of individuals, probably because they all had her contact information; based apparently on that alone, Facebook seemed to have decided they might want to be friends.
“It’s a massive privacy fail,” the psychiatrist told me at the time.
And now Facebook has access to much more data than email contacts and friends of friends. The company owns Instagram and WhatsApp, along with other smaller networks. And there's more.
In 2014, Facebook filed a patent application for making friend recommendations based on detecting that two smartphones were in the same place at the same time; it said you could compare the accelerometer and gyroscope readings of each phone, to tell whether the people were facing each other or walking together.
Read an unnerving article about Facebook's PYMK feature at Gizmodo.
(Image credit: Jim Cooke/Gizmodo)