Are there any real success stories for "ontolgies" like this? It seems like a lot of them are made, but they're ultimately not that useful. I've been forced to use some, and it seems that someone got paid a lot of money to come up with something that's incomplete and poorly models the domain. So the net change is some XML doodads that no one really wanted or needed.
One particularly compelling example that comes to mind was an ontology involving public companies, figures, events, and relationships that was combined with NLP (entity and concept identification) over semi-structured content on the ETL side, and faceted search and navigation on the retrieval side, to replace a research portal for a major UK newspaper in the mid 2000s. The results were mind blowing.