Access to museum data through the classic idea of creating a commons. A Web-based multi-institutional museum commons could open up public access to collections, deepening contextual knowledge of objects and helping museum professionals recognize the unseen value of their own collections. For example, collections items that seem orphaned or fragmentary in one institution may enjoy a rich life on-line, once reunited with relevant collections and data from other institutions in an on-line commons environment. Commons-oriented intellectual property policies should also enable content sharing for educational and other non-commercial uses, or they may be used to facilitate new innovations or for-profit businesses beyond the scope of traditional rights-and-reproductions activities.The Smithsonian Institution and the Balboa Park on-line Collaborative (BPOC) are both large, multi-part organizations with diverse research and outreach missions: together they provide a unique opportunity to explore the potential of the commons model.