It should come as no surprise that XML is yet another invention spearheaded by Berners-Lee and the organization he leads, the World Wide Web Consortium. With offices in Valbonne, France; Cambridge, Mass.; and Tokyo, and with a full-time staff of more than 60, the W3C, as it's called, brings together about 500 member organizations. While the IEEE Computer Society is one, most of the rest are large or mid-sized corporations like DaimlerChrysler [ranked 4 among the "Top 100 R and D Spenders"], Hewlett-Packard (30), and Autodesk. W3C also coordinates the work of additional researchers as well as volunteers from member and nonmember companies and academia.

The Semantic Web is just one item on the W3C's diverse agenda. Others are interoperability (in file formats, for example) and technologies for trust, like digital signatures. But the Semantic Web is increasingly important—four interest groups are working on its technologies.

Similar goal, simpler strategies

While the W3C works hard to coordinate the work of multifarious organizations, some other companies are overcoming the semantic shortcomings of a human-oriented Web without either restructuring it or waiting for smarter agents. Google Inc. (Mountain View, Calif.) has, to date, not only kept up with the Web's phenomenal growth, it has added new categories of documents in search results—PDFs, Usenet newsgroups, and image files. Autonomy Corp. (Cambridge, UK) and the Palo Alto (Calif.) Research Center [recently spun off from Xerox (73)], each, in different ways, use mathematical models of how long-term memory works in the brain to create concept maps out of the words on Web pages. At Verity Inc. (Sunnyvale, Calif.), researchers add things like organization charts and address books to infuse amorphous corporate documents with additional structure.

What companies like Google, Autonomy, and Verity are doing, in other words, is figuring out better ways of doing what search engines have always tried to do: deliver the best documents the existing Web has on a given topic. The advocates of the Semantic Web, on the other hand, are looking beyond the current Web to one in which agent-like search engines will be able to not just deliver documents, but get at the facts inside them as well. One thing everyone can agree on: even with its billions of pages and countless links, the Web, only a dozen years old, is still in its infancy. As Berners-Lee puts it, the next generation of the Web will be as revolutionary as the original Web itself was..

From words to concepts

The ideas behind the Semantic Web are innovations that simply extend current Web techniques in ways that make documents more datalike, so that agents can interact with them in sophisticated ways.

For instance, URIs (uniform resource identifiers) are like URLs (uniform resource locators), but more general: a URL (such as http://www.spectrum.ieee.org/index.html) is a link to an entity on the Web, while a URI identifies resources, in general. (All URLs are URIs, while the reverse isn't the case.) For Berners-Lee, items like human beings, corporations, and bound books in a library are resources, just not "network retrievable" ones.

XML build on a second fundamental Web technique: coding elements in a document. With the current scheme, HTML, such codes as <title> for an article's title, <bold> for boldface type and <table> to begin a table, identify document elements only stylistically. XML, however, singles things out as data elements—as dates, prices, invoice numbers, and so on. In fact, XML allows users to mark up any data elements whatsoever.