I have a database where various student musicians have their specialisms and departments listed (for example somebody could specialise in violin in the Historical Performance department). Also for example, consider Johann Sebastian Bach - he is a musician and composer in the Baroque style. Logically perhaps I'd want his specialism to fall under "Composition" and his department to be "Baroque".
I think that 'department' could be covered happily by the "category" property, but what to make of 'specialism'? That's a kind of category, too. The hCard spec says that it's cool to use 'category' twice, but it seems kind of dirty since department and specialism are so semantically unrelated.
What about the 'notes' property? Or 'role'? Thoughts?