INTRODUCTION In social tagging, in contrast to taxonomies developed by subject specialists using authorized terms (determined by professionals), people use their own keywords to describe websites for future discovery and retrieval. The resulting list of tags of information and objects is often termed a “folksonomy,” a classification done by untrained individuals (folks) . According to a December 2006 Pew Internet & American Life Project survey of 2,373 individuals, 28% of Americans have tagged content on Internet sites . Use of tagging tools was unrelated to income, age, or ethnic group. The study reported here documents how medical librarians use and perceive this relatively new way to describe information resources.