Nearly 100 people in the international ontology community met this past April 18-19 at the sixth annual Ontology Summit to discuss “making the case for ontology.” In recent years the number of deployed ontologies has increased dramatically, yet the technology is still very niche and poorly understood outside of the community. The goal of this year’s summit was to assist technology evangelists in communicating the message by providing concrete application examples, success/value metrics and advocacy strategies. The key output is a communique and corresponding talk. The main messages are: 1) ontology is about clarifying meaning and supporting inference; 2) key value propositions are shared understanding, reduced complexity, flexibility and interoperability; and 3) ontology is ready for prime time. Go forth and ontologize. Mike Uschold