Mtgox didn't follow regulatory guidance put in place by FinCEN. That is why they had their accounts frozen. BTCT is an entirely differnt conversation, as they were concerned with regulatory pressure from the SEC. Nothing to do with Bitcoin directly per se. It was the issuance and distribution of unregulated securities. That is why they shut down.
Thanks for the explanation, what do you think about bitfunder? I am quite dilemma after what had happen to BTCT.
From the perspective of a US official, Bitfunder is breaking the law. Whether or not they will comply with those laws in the future is yet to be seen. At the very least they would have to deny US customers access to their listed securities.