Plenty of stores have replaced static cardboard posters with LCD graphics and audio. But, “as you're looking at the sign, the sign’s looking back at you,” Burke says. They're not following you, per se. They are measuring how many people walk past, how many stop, and which parts of the sign catch their eye. Pair that with high-resolution cameras, and these set-ups can be sophisticated enough to make out your gender, general age, and even ethnicity, which gives retailers lots of insight about their customer demographics and what they might want.