It is still income technically, just considered a transaction for goods... I'm not sure how you could go about that subject.
I did some looking around, and it looks like you dont pay tax on virtual goods So ill see how things pan out XD
I don't sell gold, but then again if someone is making their earnings off gold selling then I would assume they would still need to pay income tax (US here) and such... I'd have to do some poking around.