Where Are The Semantics In The Semantic Web? / quote 22 of 29
Search engines don't use formal semantics
The ability of the agent to infer something about the meaning of fuel-pump depends on the existence of a formal semantics for ontology language such as DAML+OIL. The language semantics also allow the agent to infer the meaning of complex expressions built up using language primitives. The semantics of the language are not machine processible; they are written for humans only. People use them to write inference engines or other software to correctly interpret and manipulate expressions in the language. Note that today’s spectacularly impressive search engines by and large do not use formal semantics approaches. Overall it remains an unproven conjecture that such approaches will enhance search capabilities, or have significant impact anywhere else on the Web.