My first thought when I read about this ruling was, like many, "great! bitcoin is legal!". Now I'm unsure again. I've always held nagging doubts about bitcoin, and how amazingly effective it would be as a 1984-esque tool for population control and governance. To recap, just suppose BigGovt gains >51% of mining, and suddenly the only transactions getting through are government-approved transactions, to government-approved bitcoin addresses - it would be the ultimate Big Brother.  Yeah, yeah, yeah, I know, many people more clever than me have suggested measures against this, but I'm still not convinced.

So, now what, are these bitcoin "money transmitters" going to need to register their bitcoin address(es) with some government department so they can be monitored for compliance? How exactly are they going to police this ruling?

This ruling seems positive for bitcoin, but I'm seeing it more as a shot across the bow: "bitcoin: we're coming for you." In fact, many threads have said that the weak point in the bitcoin ecosystem is the fiat exchangers. How about that.

I call on the devs to prioritize a modification to the block approval code in the client, to reject blocks that do not include enough valid and well-broadcasted transactions. We need better discussion on this in order to establish exactly how to proceed.