The Web is now recognized as a cultural artifact worthy of preservation and study; however, the rhizomatic, dynamic nature of online production, the accelerating rate of innovation of the live Web, and the sheer quantity of online records all pose challenges to preserving access to online cultural heritage. Moreover, whole-Web archiving efforts such as the Internet Archive frequently miss sites that are not linked to well from other sites—including the marginalized and fringe materials that are most important in building a thick cultural history of online life. This paper argues that archives and other collecting institutions are uniquely poised to preserve online heritage in the form of cultural subject Web archives. Such institutions have the intellectual capital and the technical capabilities, as well as the cultural responsibility, to create collections that reflect the diversity of online life and that best serve potential future users. In order to build these collections, archivists and other information professionals will need a new set of skills. This paper proposes some theoretical and technical approaches to selection and access for cultural Web collections, with helpful tools and model projects to guide the discussion. / text