He posted photos of himself and friends, tagging the images with names.
But what Licata, now 34, didn’t know was that every time he was tagged, Facebook stored his digitized face in its growing database.
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Facebook is working on advanced recognition technology that would put names to faces even if they are obscured and identify people by their clothing and posture. Facebook has filed patents for technology allowing Facebook to tailor ads based on users’ facial expressions.

Saving face: Facebook wants access without limits-
Social network giant lobbies to prevent state limits on facial recognition
Basically, FB is using multiple photos of you, posted by yourself or by friends, in conjunction with artificially intelligent learning algorithms, so that FB can automatically detect your presence in photos or video feeds, anywhere they have access to the media. Each time you are “tagged” in a photo by someone else (let alone tagging yourself), Facebook uses the photo to record additional biometric details about you.
FB could sell this data base as a service to retail stores, who would now have access to the Facebook dossier that they keep on each of us. FB has the technology to identify each of as we walk in public, visit events or activities, or to track us through out all of our daily activities.
Similarly, about half of all Americans now have their likeness stored in law enforcement databases (even people never charged with a crime, let alone convicted).
Facebook is a totalitarian regime. Their goal is to be able to recognize the entire population of the earth.