Once we build all these taxonomies, thesauri, ontologies, etc. we'll run into situations where we'll have applications that need to access more than one of these simultaneously. Throw in organizational issues like different departments 'owning' their favorite organization scheme and it all gets rather messy. We'll either need to combine them or 'crosswalk' them, that is, mapping them so we know how they interrelate. I started a crosswalk page on the IAWiki to start tracking the issue.