Let's Bitcoin takes off. Say you lived in the US and had an online service that dealt in the equivalent of ~20,000 USD or more income for you (personally). What are the laws for income tax on a currency like this? Can you get in trouble with the IRS by simply having tons of BTC that the market values at (currently) almost 5$ per BTC?
According today as long you only holding bitcoin or any other cryptocurrency you don't need to pay.
Only if you sell them you need to report it.