Semantic Web and Information Brokering:
Keynote Abstract for Workshop on Semantic Web: Models, Architectures and Management, Lisbon, September 21, 2000
Tim Berners-Lee envisages Semantic Web as the next step in the evolution of the Web. He sees it to be "The Web of data (and connections) with meaning in the sense that a computer program can learn enough about what the data means to process it," and ponders, "imagine what computers can understand when there is a vast tangle of interconnected terms and data that can automatically be followed." 
Researchers in diverse areas have studied semantics for a long time. We have seen a steady progress from syntax, to representation and structure, and to semantics , in the ways we approach and solve the challenges of finding, integrating and using information of diverse types and from diverse sources. On the heels of the federated and mediator architectures, we have investigated semantic information brokering approach  to provide solutions for various information stakeholders-content creator and owners, facilitators, distributors and users.
What the concept of Semantic Web does is to juxtapose semantics and the Web. Semantics, with meaning and use of data, brings information closer to human thinking and decision making. The Web is the largest repository of data and the infrastructure of the global information system, bring. Together, they suddenly forces us to simultaneously deal with the complexity of modeling and reasoning, with the huge scale and heterogeneity of all imaginable kind.
Despite these challenges of heterogeneity and scale, and despite relative modest commercial success of federated and mediator systems, we have started to see large scale, industrial strength, albeit early, creation of the Semantic Web for commercial applications. Take two examples-Oingo  and Taalee . The latter, for the first time, provides semantics-based, pan-Web services for categorization, cataloging, search, directory, targeting, and more.
This talk provides my personal, and hence biased, views on (a) the role and prognoses of relevant standards and markups (e.g., DAML ) for the evolution of the Semantic Web, (b) how has commercial services made depth vs scale trade-off for developing Semantic Web applications, and (c) some broader goals or wish-list of Semantic Web applications and services that outline a research agenda that we are pursuing in our work on Semantic Interoperability in Digital Library services for a Digital Earth prototype .
 Tim Berners-Lee, Weaving the Web, Harper, 1999.