80% of Bitcoin trade just got regulated. I love this for more reasons than one. Here's a

to the libertarians. Pwned!
Here we go again, do you understand that FinCEN does not and cannot regulate security trading? It's not their job and they don't care. MtGox registers as a money transmitter, not a market money with SEC and CFTC.
This is clearly a step forward, well unless you are one of the bad guys who lives off by laundering black money, that is. If that's the case, Bitcoin is not for you. Go launder your money somewhere else, and keep BTC clean.
I agree it's great news! Bitcoin needs to come out of the shadows. Anonymous transactions are only useful for criminals. This is the beginning of taking Bitcoin away from Libertarian nut jobs and legitimizing it along side fiat. Coexist...not one or the other. A great win against zealots. Bitcoin may have hope after all, although I fear in the minds of the masses, the negative stigmas attached to Bitcoin may be too far ingrained. Time will tell.