Everything you always wanted to know about the semantic web but were afraid to ask...
This video from Ben Hammersly is not only VERY funny but also a good talk explaining the Semantic Web for beginners. It's a great resource to explain what the Semantic Web is all about for people who are new to the subject or simply interested in the underlying technology of RDF, the concept of triples, etc.
This should be consider in the context of Clay Skirky position on how:
The Semantic Web, with its neat ontologies and its syllogistic logic, is a nice vision. However, like many visions that project future benefits but ignore present costs, it requires too much coordination and too much energy to effect in the real world, where deductive logic is less effective and shared worldview is harder to create than we often want to admit