So what is “The Semantic Web”? According to wikipedia “The Semantic Web” is:

The Semantic Web is an evolving extension of the World Wide Web in which web content can be expressed not only in natural language, but also in a format that can be read and used by software agents, thus permitting them to find, share and integrate information more easily. It derives from W3C director Sir Tim Berners-Lee‘s vision of the Web as a universal medium for data, information, and knowledge exchange.

Maybe the following presentation will help you understand better:

The presentation was prepared by Nova Spivack who is the CEO at Radar Networks. Make sure you check his blog (Minding The Planet).