ABSTRACT
In one of the most famous instances of genre analysis in action, U.S. Supreme Court Justice Potter Stewart wrote that, while he couldn't define pornography, "I know it when I see it."' This famous phrase highlights two key points for understanding media genres: genre definitions often have palpable "real world" impact (even with admittedly weak rationales), and genre practices emerge in a wide range of sites, including legal and policy decisions. The "I know it when I see it" mode of genre definition is not limited to jurists, however, as it describes the way most people experience their own ubiquitous categorization of media. Genres are so common throughout various arenas of cultural practice that their definitions can often seem like givens-we all agree upon a basic understanding of what a sitcom is, so no further elaboration is needed.
