Earlier quoted context omitted.
It's a pity your post isn't at the top of the thread. It is sound advice. I find it fascinating that there are (apparently) people in this thread who lost $500k at MtGox and despite the loss would still have no problem paying $250k in taxes on it if they were required to do so. I would hope if you're making that kind of money you'd either have a sound sense of financial risk management, or the wisdom to hire somebody…
My comment below highlights the clawback risk for those that were successful at pulling money out. If this turns out to be a Ponzi scheme there is a real chance that people who profited and were able to get their USD out may actually be forced to forfeit all of their profits depending on the jurisdiction.
The allegations are generally much more straight forward, either some sort of incompetence in the form of transaction malleability, or some sort of malfeasance (pilfering the bank for operating costs, outright theft of the funds). Ponzi schemes these are not.