Facial recognition software, which has existed for decades, but has recently become more mainstream, is being researched and criticized for privacy issues as it is coupled with social media sites.

CNET reports:

A Carnegie Mellon University researcher described how he assembled a database of about 25,000 photographs taken from students’ Facebook profiles. Then he set up a desk in one of the campus buildings and asked willing volunteers to peer into Webcams.

The results: facial recognition software put a name to the face of 31 percent of the students after, on average, less than three seconds of rapid-fire comparisons.

In a few years, “facial visual searches may become as common as today’s text-based searches,” says Alessandro Acquisti, who presented his work in collaboration with Ralph Gross and Fred Stutzman at the Black Hat computer security conference here.

As a proof of concept, the Carnegie Mellon researchers also developed an iPhone app that can take a photograph of someone, pipe it through facial recognition software, and then display on-screen that person’s name and vital statistics.

This has “ominous risks for privacy” says Acquisti, an associate professor of information technology and public policy at the Heinz College at Carnegie Mellon University. Widespread facial recognition tied to databases with real names will erode the sense of anonymity that we expect in public, he said.

Acquisti went on to say:

“What we did on the street with mobile devices today will be accomplished in less intrusive ways tomorrow. A stranger could know your last tweet just by looking at you.”

Facebook currently uses facial recognition software as an application that can semi-automatically tag friends in pictures. Facebook has received criticism for use and implementation of this software, which was automatically loaded and users have the choice to opt out of its use, rather than opt in. And although users have the option to opt out, as PC World stated back in June, it doesn’t mean that Facebook will stop recognizing faces–just that other users won’t be prompted to automatically tag photos.While facial recognition software can save time on tagging on Facebook, the software also serves for security purposes.

For example, as the video below states, police used it to catch 19 criminals walking into the 2011 Super Bowl: