Museums want audiences to engage with their collections and ideas, but recognize that traditional methods of unidirectional on-line and in-gallery communications have limited access and dialog. Supporting social tagging of museum collections, and providing access based on the resulting folksonomy, opens museum collections to new interpretations that reflect visitors’ perspectives rather than institutional ones. This co-operation between museums and visitors bridges the gap between the professional language of the curator and the popular language of the museum visitor, and helps individuals see their personal meanings and perspectives in public collections. The steve consortium, a collaboration of museum and museum informatics professionals, is developing tools and techniques and exploring the experience of social tagging and folksonomy in the context of art museums; our research questions, prototypes and findings are also relevant to other domains.