What is a game? A definition is famously difficult. Wittgenstein, for example, after having described language as a game in his Philosophical Investigations, goes on to ask what a game is and how we know what's a game, using the word (Spiel in German) as a vivid example of the provisional and contingent nature of the supposedly clear concepts communicated by language. Game theory, a branch of mathematics, solves this question by avoiding it, providing its own definition of game, which only partially fits many or most games as we know them. And talking about games becomes really interesting when we reflect, as is inescapable since Peter Suber coined the term nomic game in 1982, that part of the action of many games, and indeed the essence of some, is in the process, play or competition of providing the game itself with its rules and hence its definition. Originally developed in reference to legislative systems as an illustration of a game of self-amendment, Suber's rule set for the game Nomic quickly took on a life of its own and spawned a small thought industry among gamers and philosophers, implicating economics, sociology and anthropology, life sciences, psychology and politics.

Markup technologies such as HTML, XML and everything that goes with them, from schemas to processing languages to public specifications and standards, have many gamelike aspects. We have players, equipment, and opportunities to compete and cooperate. When applications work as well as or better than planned, there are victories. When projects fail or initiatives collapse, there are defeats. As in many games, much of the activity of markup technologies is devoted to rules enforcement; it also, in nomic fashion, extends to breaking received rules and making new ones. (Illustrations and examples are offered at micro and macro levels.) An engagement with markup technologies, or with any media production or software application design that relies on them, demands tactics and strategy, presenting us with problems and tradeoffs enmeshed in complexities both on and off the board, and challenging us to decide not only how we play, but what game we wish to be playing. And the deeper we go, the more nomic it gets. As we ponder what we are doing with markup technologies and how they are changing what else we do – as technologists, publishers, scholars, teachers, and creative producers – it is well if we reflect on who is making the rules and how; for whose benefit; whether, when, to what extent and how we should follow their rules or make our own; and finally how the rules we make about the games we play can have far-reaching effects even beyond the game we thought we were playing.