Web ontologies: problems, benefits "Computers are insanely, hair-tearingly, stupid - they have to be told everything in precise detail...using ontology with computers can't possibly be worse than the in-code truth functions we use today. Legions of programmers are writing down things like isBossOf all the time (myself included). It's their job. Except they don't call them relations, or predicates, they call them methods and those methods capture what most of us call business logic. [Nor do they call themselves ontologists.] So it's pretty far from logic but good enough for business - until the time comes to change the logic where the cost of using all that code becomes apparent. It's a long held truism that we'd be all much better off if we could get such logic out of code."
"For my part, the raison d'etre of declaring such relations is reducing code complexity while increasing flexibility."
Bill also suggests a reading list of: Data and Reality: Bill Kent, Knowledge Representation: John Sowa, Programming in Prolog: Clocksin and Mellish Philosophy of Artificial Intelligence: ed Margaret Boden.
For those wanting to really look at vocabularies "Vocabulary Mapping for Terminology Services" which describes how combining different vocabularies can increase usefulness.