Bitcoin-central wasn't effected, as far as I can see. But this is not the point. Any exchange would have done the same if a criminal got illegal access to a brokers funds, and sold them all to manipulate prices and create havoc in the market. The only difference is that most normal stock exchanges would halt trading automatically and investigate the situation as a soon as there was unusual activity with no known reason. MtGox should behave like any other responsible exchange, and nullify the affected trades. Other exchanges roll back trades more often than you think. Even Bitcoin exchanges. It has happened on Bitcoin-Market and Bitcoin7, at least. Hopefully MtGox will implement a few safeguards for later as well, and pause trading for a while to investigate when it gets to hot.
What happens with stock exchanges is completely different. There is a period of time over which the trade is, for lack of a better term [since I don't know what the term is], held proxy. Depending upon the brokerage, if you buy a stock in the morning and then sell it in the afternoon, there is often a fee or a potential fee associated with that. Bitcoin doesn't work that way and can't work that way [there is no such thing as a transaction reversal ... just a new transaction that where a trade could be opposite of the original thus leaving a net of 0BTC changing hands]. Even with a brokerage, your stock is available for sale immediately. Unless an exchange requires you to leave your BTC and USD from trades in their exchange for a period of time to supposedly mitigate something like the crime that occurred, they can't solve that problem. I for one do NOT trust my funds (BTC or USD) in Mt.Gox or really any exchange for any period of time. I have been given every reason NOT to trust it to be held safely and every reason to move funds in and out as quickly as possible.
Of course there are complications, which would have to be handled on a case to case basis.
With high volume, we see how fast that can be done. Volume is only going to increase. Sorry, case by case is not a solution.
Did anyone lose anything? People who traded at a loss on other exchanges based on a sudden change from 17.5 to 0 on mtgox should know better, IMHO. I don't think you will many, with the exception of mtgox, who actually lost money on the rollback. More likely a lot of people suffered a loss due to the unusual buying and withdrawals from stolen accounts during the previous days, but this would be impossible to prove.
Clearly people did since they have a claims page setup. Also, private information was lost which is a clear breach of trust, and it was done via a breach of a security auditor's computer?! Even if true, which I have significant doubt about, that auditor will NEVER have another client again. The effect on the market is damage to some and benefit to others. You claim they should know better. How do you know that bitcoin isn't collapsing when you see something like this happening [say the government steps in and shuts down key network points to stop bitcoin trading and mining]. Nobody knows whether bitcoin will grow to a feasible online currency or go bust like previous virtual currencies. It is riskier than the stock market BY FAR if you are investing money in it. Tangible losses? At least one person lost approximately $1000 worth of BTC it sounds like [at what USD price ... how many coins?]. It looks as if several accounts were used, so it seems several accounts suffered a loss.
