Imagine walking into a store and the shop assistant walks over and says, “Hi Simona, here's a cappuccino for you. It's just the way you like it, with extra foam.”

She consults her smart phone for a second and then says:

“I know you put on two extra kilos over the holidays, but we have some navy blue banded tops on sale that are really slimming. Navy is your favorite color, am I right?”

“Sure,” you sputter. “Wow, she knows all about me.” The funny thing is, you have never seen this woman before in your life.

This scenario could soon be a reality if more and more retailers adopt facial recognition technology by companies like Japan's NEC (TYO:6701) and California-based FaceFirst.

The BBC reports that both companies use cameras placed at the entrance to stores. Facial recognition software then compares the shoppers to a database of photos from sources like Facebook, the article suggests.

Are you a materialist or a criminal?

The technology recognizes “important visitors,” i.e. customers likely to spend a lot. These customers would get VIP treatment, a free cappuccino, discounts and personalized attention. This means that in the future, if you walk into a store and the sales associate totally ignores you, you might have reason to take in personally.

The technology can also be used to nab potential shoplifters before they commit their crimes. If you have a police record and walk into a high-end shop, this software could scrutinize you extra-carefully. As one marketer put it, “What about privacy? There's no such thing anymore. At best, privacy is a cherished illusion, and it's fallen by the wayside as people volunteer more personal data in the interest of greater personalization and convenience.”

In other words, you may think you're walking around a city anonymously, but you're actually being followed by a virtual data trail.