Conventional theories of money assume that money is backed by precious metal (the theory known as bullionism) or by the state (chartalism) but Bitcoin is backed by neither. Economists also often define money as anything that serves as a medium of exchange, but Bitcoin isn't much good at that either (so far, at least). So does that mean Bitcoin is not money, or is the problem with these theories?
I have posted a paper on this question here, comments/responses appreciated: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2624371