World Wide Web inventor Tim Berners-Lee would like to see the global content network he helped develop turn into a giant transactional database.

In a design paper written six years ago, Berners-Lee described his vision of the Semantic Web, an initiative the World Wide Web Consortium (W3C) has been steadily laying the framework for ever since. At the 13th annual World Wide Web Conference running this week in New York, Berners-Lee devoted his keynote address to detailing the Semantic Web's rationale and the progress and challenges involved in its creation.

The past few months included an important milestone for Semantic Web development. Two foundational standards, the Resource Description Framework (RDF) and the OWL Web Ontology Language (OWL), became W3C recommendations in February, a sign that the group considers them ready for widespread adoption.

"There was a lot of pain and sweat and tears and discussions and arguments" in getting RDF and OWL to the level of accepted standards, Berners-Lee said. He expects phase two, now in progress, to be more fun: "I hope it'll be very exciting. We'll start to get more satisfaction back from actually building applications and seeing them connect together."

The aim of the Semantic Web is to add metadata to information placed online, to allow it to be readable by machines. That context would enable automation of a variety of interactions. An online catalog could, for instance, connect to a user's order history and preferences to a calendar, to automatically pick out available delivery times.

Projects involving Semantic Web technologies are already under way at several organizations, including Boeing, which is exploring semantics-based applications for information and application integration and interoperability, and for knowledge management. Adobe has boosted some products with XMP (Extensible Metadata Platform), an RDF-based metadata system that links contextual information with content files.

Partially as a proof-of-concept for the Semantic Web, conference organizers are at work on a Web archive of photos from current and past gatherings, complete with metadata annotations.

Berners-Lee encouraged attendees to go out and Semantic Web-enable anything they can online. "We're going to have to bootstrap things in the short term," he said.

While most of Berners-Lee's speech focused on Semantic Web development, he touched briefly on other Web infrastructure issues, including Internet Corporation for Assigned Names and Numbers' push to expand the Web's pool of top-level domains (TLDs).

Berners-Lee said he's wary of the fragmentation that comes with TLD expansion, and prefers to see domains added only when they're needed for innovative social or technical systems.

He also praised the work done on advancing several past W3C initiatives, like Cascading Style Sheets, a standard now widely used.

"It's worth celebrating that, actually, we've come a long way with some of this stuff," Berners-Lee said.