• by Erik Sass , Staff Writer @eriksass1, August 5, 2011

While lots of people have been wringing their hands about Facebook's deployment of facial recognition technology, which strikes many as a breach of privacy, I have generally been more sanguine: as long as it all occurred within the social network, and as long as you could disable the facial recognition if you want, it didn't seem like that big a deal to me.  But a new study by Alessandro Acquisiti of Carnegie Mellon University points out that facial recognition raises privacy concerns that aren't so easy to dismiss.

For one thing, facial recognition can clearly be applied to images found across the Internet, not just Facebook, and then used to match information from one location with images found on another. Here, Acquisiti and his team were able to use standard, off-the-shelf facial recognition software to compare photos from Facebook and dating Web sites and identify individuals, even if they tried to obscure their identities by using different names.

Even more disturbing, from my perspective, was a second experiment in which Acquisiti and his team took photos of individuals and then compared these offline and online images; this time, they were able to discover the identities of people on Facebook with photos they provided themselves. This effectively extends the reach of photo recognition from the online world to the offline world: it's not hard to imagine someone surreptitiously snapping photos of someone out in the "real world" and then feeding them into image identification software to pull up their Facebook profile or other identifying online information.

Building on the real world-online bridge created by facial recognition, Acquisiti's team then was able to "infer" a surprising amount of data combed from other online sources, demonstrating "that it is possible to start from an anonymous face in the street, and end up with very sensitive information about that person, in a process of data ‘accretion.'"  Acquisiti's study represents a warning about the still largely untapped power of "this blending of online and offline data -- made possible by the convergence of face recognition, social networks, data mining, and cloud computing."

Facial recognition also adds yet another lay of permanence (not necessarily in a good way) to the online "paper trails" people leave behind them, for good or ill, in the social media universe. It's bad enough to have your name attached to some thoughtless remark online; now you don't even have to provide your name for people to be able to link your picture to incriminating content. On that score, Acquisiti writes: "Google's Eric Schmidt observed that, in the future, young individuals may be entitled to change their names to disown youthful improprieties. It is much harder, however, to change someone's face."