Ontology and the Web

Computerworld - The gist of last week's column was that the disorganization of information on the Web is at the heart of the growing pains we're experiencing in the Internet economy. As I mentioned last week, a Scientific American article, "The Semantic Web," by Tim Berners-Lee, James Hendler and Ora Lassila (www.sciam.com/2001/0501issue/0501berners-lee.html), proposes a way to make that information more accessible, which would empower programmers to build more intelligent software.
The goal of the Semantic Web's supporters is to make it possible for software to find the data it needs on the Web, understand it, cross-reference it and apply it to a particular task. The means to this end are a combination of XML, Resource Description Framework (RDF) and a concept called ontologies.
Assuming that everyone publishes data on the Web in conformance with the standards, I should be able to tell my Web-enabled handheld device to schedule an appointment with a dentist within 20 miles of home and let the computer do the rest. It should be able to interact with the data on the Web to find a doctor who belongs to my insurance plan, resolve schedule conflicts, make the appointment at both ends and compile driving directions to get there.
Think of the Semantic Web as a project to deploy workflow management and enterprise resource planning software on a global scale, except in this case, there's no single authority over the various departments where the data is kept. On second thought, don't think of it that way; it would probably spoil your next meal.
Obviously, I'm not optimistic. If you read last week's column, or any of my other columns dealing with XML, you already know that I'm deeply unimpressed with XML as an enabling technology for sharing information. I'm not at odds with the authors of the aforementioned Scientific American article on this point. The article itself points out that XML alone is inadequate for the job. XML is great as a standard way of saying, "This next thing is a widget." But XML doesn't require that you describe what the widget does, how it works or that the widget itself conforms to a standard.
RDF helps this situation a little. RDF is a complementary standard designed to describe the widget in terms of a subject, predicate and object. If I'm in danger of losing you at this point because you've forgotten your grammar lessons, don't worry, we're not going there. If you're curious about the details, visit www.w3.org/RDF.
Otherwise, think of it this way: When XML points