Literacy is a measure of being literate, of the ability to read and write. The central activity of the humanities—its shared discipline—literacy has become one of its most powerful and diffuse metaphors, becoming a broadly applied metaphor representing a fluency, a competency, or a skill in manipulating information. The word “literacy” is of recent coinage, being little more than a century old. Reading and writing, or effectively using letters (the word at the root of literacy), are ancient skills, but the word “literacy” likely springs from and reflects the emergence of mass public education at the end of the 19th and the turn of the 20th century. In this sense, then “literacy” measures personal and demographic development. Literacy is mimetic. It is synesthetic—in some languages, it means hearing sounds (the phonemes) in what is seen (the letters); in others, it means linking a symbol to the thing symbolized. Although a recent word, “literacy” depends upon the emergence of symbolic sign systems in ancient times. Written symbolic systems, by contrast, are relatively recent developments in human history. But they bear a more complicated relationship to the spoken language, being in part a representation of it (and thus a recording of its contents) while also offering a representation of the world, the referent: that is, literacy involves an awareness of the representation of the world. Reading and writing are tied to millennia of changes in technologies of representation. As a term denoting fluidity with letters, literacy has a history and a geography that follow the development and movement of a phonetic alphabetic and subsequent systems of writing. If the alphabet encodes a shift from orality to literacy, HTML encodes a shift from verbal literacy to a kind of numerical literacy not yet theorized.