I was there on that fateful day, were you?
The problem with this whole scenario is that, from the developer/publisher perspective, they want to reinforce the idea that "virtual items" or ingame content is THEIR property, not the property of the players.
This proposal throws that idea into doubt (and exposes the EULA to legal inspection), despite the fact that "ownership" is not needed to be taxed of generated revenue.
I have no idea what will come from this, but I can say it won't play out as currently envisioned. Devs/Pubs will resist the idea based on the fact that their required tracking runs counter to their overall position. The majority of the companies that run the virtual trade operate overseas, thus outside of US taxation anyway.
Glad to see US tax dollars uselessly at work, as usual. Hopefully, the whole thing ends up with an examination the EULA, and the exclusion of legal rights it attempts to force. That's about the only good I can see coming outta this.