I have written a few times about our work in Web services semantics and the specification we jointly authored with a group of colleagues from the University of Georgia. We submitted this specification, called Web Services Semantics- WSLD-S, to the W3C which has acknowledged receipt and has published it as a member submission. WSDL-S defines how semantic annotations can be added to WSDL documents to define the meaning of the inputs, outputs, preconditions and effects of the operations described by the Web service interface. Other specifications have also been submitted to the W3C including OWL-S, WSMO and SWSF. However, WSDL-S is the only one that takes the existing WSDL and XML schema-based Web services standards as the starting point. This is not to preclude work on initiatives that have a wider scope, like OWL-S, WSMO and SWSF, since WSDL-S could act as a bridge to those approaches. It give semantic Web services a basis in the currently deployed base of services.
At the W3C Workshop on Frameworks for Semantics in Web Services, held this past June in Innsbruck, the attendees agreed that linking a Web service description to a domain ontology was the initial requirement for semantic Web services. It is also a concept in common among all the approaches presented at the workshop. As one of the authors of the WSDL-S specification, I hope it helps move this area forward and serves as a way to help focus discussions on getting a good first step under way.