Mt.Gox was once commonly know as "Magic the Gathering Online Exchange" and was a website setup to trade cards. The Bitcoin dabbler who bought the domain didn't bother to change it.) And as a card exchange, the site generated just pennies a day in income.
On 19 June 2011, a security breach of the Mt.Gox bitcoin exchange caused the nominal price of a bitcoin fraudulently to drop to one cent on the Mt.Gox exchange, after a hacker allegedly used credentials from a Mt.Gox auditor's compromised computer illegally to transfer a large number of bitcoins to himself. He used the exchange's software to sell them all nominally, creating a massive "ask" order at any price. Within minutes the price corrected to its correct user-traded value. Accounts with the equivalent of more than USD 8,750,000 were affected.
On Feb 22, 2013, following an introduction of new anti-money laundering requirements by Dwolla, some Dwolla accounts became temporarily restricted. As a result transactions from Mt.Gox to those account were cancelled by Dwolla. The funds never made it back to MtGox accounts. Mt.Gox help desk issued the following comment: "Please be advised that you are actually not allowed to cancel any withdrawals received from Mt.Gox as we have never had this case before and we are working with Dwolla to locate your returned funds." The funds were finally returned on May 3, more than 3 months later, with a note "Please be advised never to cancel any Dwolla withdrawals from us again".