'Shadow profiles' are anything that Facebook got without asking for direct permission to get. It could come through a friend list on Facebook back when you cou

'Shadow profiles' are anything that Facebook got without asking for direct permission to get. It could come through a friend list on Facebook back when you could do that or through harvesting the contact lists on mobile. Both are shadow profiles and both weren't granted access but Facebook got to it (or app developers did) via a friend permission or from the native mobile apps contact list harvesting and tracking. The most you could get about a user that wasn't part of Facebook was their email, name and anything in their contact list and they probably eventually tracked that user through various means, many companies still do this and other bigs did as well such as LinkedIn. Even on LinkedIn though, one initial user had to use their app or their import feature to get to the 'shadow profiles'. Most 'shadow profiles' came from initial granting by a 'friend' or associate. They are both 'shadow profiles', anyone that got their data pulled without being directly asked is one. Facebook shut down the friend list and global user id tracking/correlation nearly 5 years ago. Most of the problems were back in 2007-2014 when app development on Facebook was bigger and games were huge there because of this.