The halls and meeting rooms at the XML Web Services One conference in San Jose were abuzz with discussion of RDF technology, and the keynote presentation by Willaim Ruh, Sr. VP of Professional Services at Software AG, focused on the importance of semantic Web technologies to the future of Web services.

Throughout the conference both speakers and attendees were discussing RDF and showing themselves knowledgeable of the technology, and even higher-level ones such as DAML+OIL. In what might be a surprise to some, at least two prominent sessions by Microsoft speakers made significant mention of RDF and its possible role in Web services. Don Box mentioned it in his keynote on Web services technologies and Karsten Januszewski mentioned it in his session on UDDI in .NET.

In Ruh's keynote, entitled "Semantic Web - A Good Vision, But How to Get There?", Ruh plumbed these ideas further, from a business rather than technical point of view.

In an interesting and clever twist, Ruh held up the US dollar bill as the perfect exemplar for what semantic Web technologies should ensure. He pointed out that it is:

• self-describing
• hard to forge
• convertible
• issued by a trusted authority
• a world-wide standard
• easy to understand
• machine readable

Ruh stressed that the Semantic Web is not a new Web but an extension of the existing one. He also clarified that it is about allowing machines to comprehend semantic documents and data, and not about understanding natural human speech and writing. He stressed that the Semantic Web need not be a rehash of classic (and some would say discredited) AI.

Ruh said that the Semantic Web involves structured markup, metadata and "knowledge about knowledge". He said the cornerstones are ontologies, RDF and XML, in that order, top to bottom, as a layer cake. He defined an ontology as a document that formally defines the relationships between terms.

Ruh did mention several factors that could impair the Semantic Web. He pointed out that we produce 1 exabyte of digital information each year, and that most of it is not marked up as structured documents. He also pointed out that understanding and buy-in to the cornerstone technologies of the Semantic Web seemed to stop at XML in too many organizations. Finally, he said that most projects, programming time is wasted because of impedance mismatches between code and the concepts underlying the code. He called out a tendency for people to try to separate data from applications from business process, saying this is wrong-headed and costs a lot of problems in IT, especially for integration.

At this point Ruh asked how many people in the room had known of RDF before attending the conference. A bit less than half the nearly 200 present raised their hands. Ruh acknowledged that the high proportion surprised, but pleased him.

Ruh pointed out that RDF and Ontologies support making business processes work better, and combine more smoothly with data and applications. He claimed that "XML document[s are] the foundation for process-centric architectures" and showed how XML integrates data, metadata, process, linking and applications. He pointed out how the document view of Web services takes advantage of this power better than the view of Web services as a bunch of discrete, procedural APIs.

Finally, Ruh gave a list excerpting from the many vertical industry initiatives working on basic ontologies based on XML, including automotive, chemical and petroleum exchanges, retail, finance, furnishing, health care, telecommunications, insurance and e-commerce. He also discussed how the architecture he advocates might be implemented using XML server and broker technology, and gave an example of how Software AG used this approach in deploying their Tamino XML products for DaimlerChrysler.