Mt. Gox is the oldest, largest exchange that has lost about 350 million dollars in BitCoins, with over 744,000 bitcoins lost.
This is due to a flaw in the bitcoin code, that allowed bitcoin theft to occur for years.
Mt. Gox KNEW about this flaw but failed to report it.
Obviously the bitcoin community is rallying to improve code to maintain system order.
I believe this is a mere blip in the advance of bitcoin, and I hope we see many more of these issues exposed sooner rather than later. For each time a flaw is exposed, it will be resolved making Bitcoin, and by leadership all other crypto currencies to become more resilient.
I need to get myself connected via any trading exchange ASAP to start getting bitcoin while the price is suppressed at $553, for I am confident bitcoin will advance easily back to double of what it is today in short order.