Hi Paul, what you're talking about amounts to a simple ontology (as opposed to a complex one). This is an approach a linguist might use to solve tagging ambiguity problems where polysemy and homography cause confusion. By taking other tags for the same image (for example) and seeing whether any of those cluster in the same sub-branch of the ontological tree structure, you can disambiguate them.
The problem is often a case of the tagging system not being able to guess at what the user wants. In my fantasy system, you would enter something like "jaguar" and the software would then ask whether you meant the CAT, or the CAR, or the COMPANY. Or whatever...
And all of this requires a pre-existing ontology. WordNet might help with this. :)
