All it takes is the swipe of a finger. We connect with friends. We buy the latest gadgets and gear. We find out what's happening in the world. But with that same simple swipe, we cast an increasingly expansive shadow. With each connection, we leave a digital trail that tracks our every move and milestone, our every like and dislike. And it's not just people. Today, all major cities are networked. Urban infrastructures are monitored and controlled by complex operating systems.