In this article we use the rhetorical notion of genre as an analytic lens for studying the use and impact of new media in schools. Genre pervades the scholastic life of students as they become adept practitioners of written performances. Our empirical studies investigate how creation and consumption of media are linked as high school students produce a public information resource in their science classes using a specially designed wiki. We found that, although institutional assessment regimes for both students and teachers inhibited collaboration and although the wiki tools were appropriated as single-author environments, the wiki, because it is an open, transparent medium, supported students in building a shared understanding of genre as they struggled with an unfamiliar rhetorical situation. As we describe the process by which students made sense of an assignment that served purposes beyond test preparation and classroom assessment, we also demonstrate how writing on a public wiki was a particularly useful writing experience that brought about opportunities for reflection and learning. These opportunities include transforming the value of citation, creating a need to engage deeply with content, and providing both a need and a foundation for assessing information resources.