The USA's Internal Revenue Service has, albeit belatedly, joined its Treasury sibling, FinCEN, in concluding that there really is no material difference between using virtual currencies and USD or other currencies. In a notice issued this week, it's made clear: if you price and are paid for your goods or services in bitcoin or any other virtual currency, you are liable for trading profits in exactly the same way as if you priced them, and were paid, in fiat currencies.