“Bitcoin, the IRS says, is property, not a currency. And as such, when you buy something with the volatile digital currency it’s most likely a taxable event. That sounds like a bookkeeping nightmare, but as with so many of the twists and turns that face bitcoin as it matures as a digital currency (er, property) it’s also an area where new bitcoin startups could step in. ‘I think this is going to create a huge opportunity for hosted wallets,’ says Jered Kenna, a bitcoin entrepreneur and the CEO of Moneyandtech.com. He believes that the smart bitcoin wallet makers will simply be able to add this as a service, tracking the capital gains and losses as you spend your bitcoins through the year.”
http://www.wired.com/wiredenterprise/2014/03/irs-bitcoin/