This issue of taxing is what drives the governments crazy about the existence of Bitcoin. Day-in and day-out, the governments are looking for means to impose regulations on Bitcoin in order to tax its users. However, Bitcoin is designed in a way that imposing tax on its users will be very difficult unless it stems from the exchanges where users convert their tokens to fiat. Anyway, users are already being charged some fees with each transaction on the exchange sites, so probably, another form of indirect tax payment.