Profits from cryptocurrency is taxed nearly in every country.
(it seems "tax" is in english sometimes used as synonym for fee? otherwise I can't explain why so many people claim "there is no tax only fee for withdrawal/trading". This does not make sense, since real tax has nothing to do with any fees)
@vsyc:
It does not depend on where you are, it does depend on where you live (usually this is where you have your home or where you are more then half a year per year). You pay the taxes to that authority were you also pay all other taxes to.
Got it, so lets say I sold my GNT for BTC, in country that has tax 50% on income, and went to live in country that has tax 20%, after half year I decided to sell my BTC for fiat in latter country?
My point, if I understand this right, that there is no government/institution in the world to control profit when you sell one crypto for another. But there is capital gain tax/income tax when you sell crypto for fiat and do profit from that?
Speaking of half year, in some countries I can stay for half year as a tourist

lets say in US/Canada, how that works in this case?
It's best to really even really live in countries where Bitcoin can be legally used, because there are opportunities to obtain criminal penalties for illegal financial transactions in some countries.