See my other comment here [1]. The IRS removed that part to avoid freaking people out and because they don't actually care about the trivial amount of money being made on game currencies, not because it was an incorrect interpretation of the law. If you make $100K arbitraging V-Bucks you have always needed to pay tax on that, same as any other capital gain.
This has nothing to do with whether or not you pay tax. You pay tax on income even if it is not related to digital currencies.
If you somehow made $100k off V-Bucks then you need to report that income, but you should say "No" to the question about digital currencies.
(Disclaimer: I can't believe I have to say this, but if you are making significant money off of video game currencies you should talk to a professional rather than listening to an anonymous HN poster as your sole tax advice)
That question in form isn't about currencies, word used is "asset". People here are understanding that fundamentally they need pay taxes from any income, but that "Digital Assets" question seems overly broad and seems cover even non-income situations ("gift or otherwise dispose" for example).
Additionally, I think that your definition of "digital currencies" is little bit strict. IRS isn't going to look definitions, that exclude taxable income.
User semiquaver already posted snippet from "Bloomberg Tax", showing potential interest for gaming currencies.
