What is the semantic web?

Free Definition explains:

The Semantic Web is a current project under the direction of Tim Berners-Lee of the World Wide Web Consortium to extend the ability of the World Wide Web by developing standards and tools that allow meaning to be added to the content of webpages. The goal of the semantic web is to create a universal medium for the exchange of data by allowing meaning to be given, using tools and tags, to the content within webpages.

Currently the world wide web contains html, which is a language that is useful for displaying graphics and text but does not lend any meaning to the content it describes. The semantic web will address this issue by allowing content to be described in XML documents using tools like RDF and OWL which are types of tags. These description tags that lend meaning to the content facilitates automated information gathering and research by computers.

Now you know.