As you pass the shop window, a beautiful coat catches your eye. You stop, gaze at it a while, spot the price and, regretfully, move on.
Little do you know that WiFi sensors in the window have used your smartphone to detect your presence outside the shop. Not only that, but they have clocked how many people as well as you have looked at the display, how many have then entered the store, and how long they stayed there. They may even be prompting store managers to lower the price.
This scenario, described by the FT’s Companies Editor Sarah Gordon in the introduction to the FT’s latest ebook, Decoding Big Data, is not a vision of how shopping will be monitored in the future. It is how stores are tracking shoppers today.