Women always have long hair, right?
OK, obviously that's not true but hair length is one of the features that new supermarket advertising software will use to classify you. As you queue at the till, a camera will scan your face. The computer will then estimate your age and gender, before bringing up adverts tailored to what statistics say you'll be interested in.
I know the internet is full of targeted advertising; I'm used to that. But I'm not sure I like the idea of a computer looking at my face and guessing my age!