On March 24 & 25, 2011, the Open Annotation Collaboration (OAC) project held a one and half day workshop at the Illini Center in downtown Chicago. The purpose of this workshop was to bring together scholars, librarians, and systems designers involved in ongoing digital content projects using or planning to implement annotation tools and services. Participants were asked to talk about their projects dealing with annotation and to provide feedback to the OAC on data modeling work of the Collaboration to date.