An account was compromised, and despite there being no government regulation, the exchange stepped in, protected their customer, rolled back the trades and protected the market.
That is anarchy exactly! But no burning world. And it is yet another realworld test that has been successfully met by the bitcoin idea.
I'm not sold on bitcoins viability, due to questions about the larger marketability and having not done an audit of the software. But from an economic perspective, bitcoin is a viable currency, or as close to meeting all the requirements that any non-physical currency can.