As someone who spends most of his waking hours listening to Pandora, I haven't just accepted the idea that algorithms can get me what I want, but pretty much depend on them. Still, I'm only coming to terms with the idea that these sorts of algorithms will increasingly find their way into mundane physical spaces, like supermarkets, to shape our decisions in real-time. What if, ten years from now, walking into a supermarket meant getting a series of customized alerts and pitches designed to tempt you with your favorite comfort food? How would that change what we eat--and how healthy we are?