I have implemented hAtom microformat on my blog. At least, I think I have, but I can't find any validator (or any software that uses hAtom) in order to determine if I have done this correctly. A Google search for "hatom validator" currently doesn't return anything useful. Does anyone know of a way to confirm that it is implemented correctly?
Convert it to Atom, validate Atom and manually check if it contains all data you expected.
There's open-source hCard validator. Maybe someone could adapt it to validate hAtom as well…