Literacy used to be the domain of scribes and priests. Then the world became more complicated and demanded that everyone read and write. Computing is also a form of literacy, but having it only understood by a priesthood of programmers is not going to be enough for our complex, online world. "Learn to code" has become a mantra for education at all ages. But after clearing away the hype, why do people need to learn to code? What does it get us exactly?