The Rhizome ArtBase is one of the largest online archives of new media art. Ranging from net art to software art, computer games, and documentation of new media performance and installation, its 1,600 works are selected according to their "potential historical significance." Similar to the TextBase, an online archive of the content that has appeared on Rhizome’s mailing lists over the last 10 years, the archive can be searched by keyword, in addition to artist’s name and work title. Each artwork is made accessible on the Internet either as "linked" or "cloned." The files of cloned projects—as opposed to those that are linked to the artist’s site—are maintained in perpetuity on the Rhizome servers; the artist decides whether to "link" or "clone" a project. Since the ArtBase’s inception in 1999, the organization has been active in new media art preservation. Some of these efforts include Richard Rinehart’s "Preserving the Rhizome ArtBase" (2002), a commissioned report on the methodology and practices of archiving new media art online, and the Guggenheim Museum’s Variable Media Network, which is comprised of a number of North American institutions and focuses on the question of sustainability of all forms of media art.