He linked to that post in his, but that proves the data is transferred, not that it is stored. The article I missed, though, does make the claim that Facebook stores the data, and it is associated with a user.
I don't think it's possible to figure out if it's stored, as facebook would have to own up to it, and why would they. This data gives them massive power, why wouldn't they store it? If I were them I would.