"Say you're at a gas station. Say you're buying some supplies—bottled water, coffee, maybe some M&Ms—before you head back to your car. And as you're buying your loot, an ad pops up on a screen next to the cash register: it is really relevant to you. Like, really relevant. 

It could be because of luck, but it could also be because the screen has sensed your age and your gender. Tesco, the U.K. supermarket chain, has just announced that it will be installing screens with facial recognition capabilities in 450 of its gas stations, reaching some 5 million customers. The purpose? To serve ads that are tailored to those customers' particular demographics.  

"It's like something out of Minority Report," Simon Sugar, CEO of Amscreen, the company that provides the ad-targeting technology, declared of the system.

Except, of course, it's no longer just like something out of Minority Report. It's also like something out of the world we live in, every day. (Sugar: "This could change the face of British retail, and our plans are to expand the screens into as many supermarkets as possible.") Facial recognition systems may still unsettle us, in that they transform the most visually expressive aspects of ourselves—our faces—into data. But they are here. Their uses will likely only expand."

So, profiling.

The implication is that once cross-referenced with Facebook, they know what you really like.

The thought of never being able to turn Facebook off wherever you go is a scary one.