I think a more plausible explanation is location reporting from your phone or laptop. Unfortunately, Facebook's official explanation of "People you may Know" i

I think a more plausible explanation is location reporting from your phone or laptop. Unfortunately, Facebook's official explanation of "People you may Know" is chalked up to "many other factors". So I don't blame you for speculating. https://www.facebook.com/help/163810437015615 https://www.facebook.com/help/163810437015615 I wish they would update this page to be more transparent. If they are in fact using LinkedIn's network (I just saw your comment below about co-workers which are not in the same geographical location), I hope they let users know and make a feature to opt-out of mixing it with Facebook.