Semantic web technologies as the foundation for the information infrastructure

The Semantic Web is arising over the pas few years as a realistic option for a world wide Information Infrastructure, with its promises of semantic interoperability and serendipitous reuse. In this paper we will analyse the essential ingredients of semantic technologies, what makes them suitable as the foundation for the Information Infrastructure, and what the alternatives to semantic technologies would be as foundations for the Information Infrastructure. We will make a survey of the most important achievements on semantic technologies in the past few years, and point to the most important challenges that remain to be solved.