Fraudulent trading activity at Mt. Gox
The reason I'm inclined to believe this report's implications about Karpeles is because I spent a long time in Mt. Gox's IRC support channel talking with support reps, and they were paid to lie.  They didn't know they were being paid to lie, but they were instructed by management to say "don't worry, all user coins are safe" right up until the day the Mt. Gox crisis report was leaked.  They could have said "we are investigating the extent of the problem," but no, Karpeles was paying them to say "nothing is wrong," even while Karpeles was crafting his crisis report to investors about how all the coins were gone.Karpeles seems to have a history of lying.  He was caught in a lie by his employer in 2004: http://newslines.org/mt-gox/joins-linux-cyberjoueurs/From a game theory point of view, it's interesting that the price at every major exchange depends on every other major exchange.  For example, when Mt. Gox was active, if its price went up, BTC-e, Bitstamp, etc would simultaneously go up.  It's a natural phenomenon which has rather grim implications: if an exchange is conducting fraudulent activity, then the entire bitcoin trading ecosystem is affected.  And since bitcoin is completely unregulated, there's nothing really stopping anyone from manipulating the market.  For example, no one knows who's behind BTC-e, but it has a lot of trade volume.  What if they're engaging in fraudulent trading as well?  There's every incentive to.The inevitable conclusion seems to be: you can try to come up with a bunch of logical reasons about why the price of bitcoin is going up or down, but you can't ever rule out "the price is due to large-scale fraudulent behavior," i.e. it's a bubble.  Bad behavior from one exchange will always affect all the others.As Karpeles has probably shown, you can become a millionaire by manipulating the market and then escape all consequences by letting your company go bankrupt.