As knowledge engineering moves to the Semantic Web, ontologies become dynamic products of collaborative development rather than artifacts produced in a closed environment of a single research group. Today the development of many large ontologies involves some component of community-based development. However, the projects differ—sometimes significantly—in the way the community members can contribute, the different roles they play, the mechanisms they use to carry out discussions and to achieve consensus. We are currently developing a flexible mechanism to support a wide range of collaborative workflows in the Protege environment. In this paper, we analyze workflows for several active projects, and describe the properties of these workflows. We then discuss an ontology that we developed to represent different aspects of workflows for collaborative ontology-development. This ontology is a key component of the customizable workflow support in Protege. We evaluate the coverage and flexibility of this ontology by using it to represent formally two different collaborative workflows described in the literature, DILIGENT and BiomedGT. This evaluation demonstrates that our workflow ontology is sufficiently flexible to represent these very different workflows.
