Abstract
The release of OWL2, the latest incarnation of the Web Ontology Language, in the fall of 2009 delivered a new set of features drawn from user communities, researchers, and developers. These features build on and extend the original version in a way that is not only more expressive, but also addresses the burden of implementing the full language through tractable subsets for more efficient reasoning. Increased understanding and a focus on scalability has also moved OWL from toy applications towards large scale knowledge bases for data verification, question answering and knowledge discovery.