I've been thinking more about MtGox and the missing coins today. I described a theory earlier that the only theft of coins occurred in 2011. Since then, MtGox has been running a slowly-dwindling fractional reserve:
https://bitcointalksearch.org/topic/m.53978691. Why is Mark acting so strange about releasing details of the theft? Why does he insist that the coins are just "temporarily unavailable"? How much of an impact did malleability play?
Answer: if he admits that the theft took place in 2011 and that he knew, then he is guilty of fraud and will very likely spend time in jail. If it's plausible that he wasn't aware of the theft until now, then he is only guilty of incompetence and negligence, and will likely not end up in jail.
I think the malleability thefts were a feature and not a bug. He wanted people to steal coins in this way, to obfuscate the large theft from 2011. And he also wants people to think that
he thinks he made a mistake somewhere and certain "cold-storage" keys are still on his server. He knows the coins have been gone for a long time, but he wants to create enough doubt in everyone's mind that he won't be found guilty of a fraud that wiped out half a billion dollars.
2. What kind of person could lose 500,000 - 1,000,000 bitcoins? How could the "cold wallet leak"?
Answer: People are amazed that 750,000 BTC could be stollen. However, if we assume the theft happened in the summer of 2011, then this is actually very believable and perhaps Mark was more "unlucky" than negligent or incompetent. Remember, in April of 2011, bicoin was trading at about $1, and in October 2010 at $0.10. So, 750,000 BTC would have only had a value of about $75,000 when Mark wrote the original code.
At $75,000, I can see a lot of people saying "oh, just leave the keys on the server." Then suddenly the price starts to rally hard and months later the price is $30 per BTC and those coins are worth $22.5 million. Mark is working frantically to code a more secure system because he doesn't want to lose $22.5 million! But his business grew too fast and he couldn't get it all done.
And then "bam!" As he's working to implement better bitcoin security in the summer of 2011 to protect what are now millions of dollars of coins, the theft occurs. A few years later and the 750,000 BTC that he stored on his server at $0.10 a pop are suddenly worth $400,000,000!
And that's how you go broke with a bang ladies and gentlemen!