WSMO or Web Service Modeling Ontology is an ontology currently developed to support the deployment and interoperability of Semantic Web Services. The WSMO working group, part of the ESSI Cluster aligns the research and development efforts in the areas of Semantic Web Services between several European FP6 research projects. WSMO working group includes the WSML working group, which aims at developing a language called Web Service Modeling Language (WSML) that formalizes the Web Service Modeling Ontology (WSMO).