There is a great article in Boxes and Arrows this week, which explains the idea behind ontologies in the Semantic Web, which is being pushed by Tim Berners-Lee.
The article titled, Building a Metadata-Based Website has been written by Brett Lider and Anca Mosoiu and discusses the differences between Meta-data websites and traditional CMS by looking at the advantages between the two and looking at business models that could result. The article also contains a great reference list of further readings on the Semantic Web.