Maybe Bitcoin isn't the way of the future? Concerns about the virtual currency’s security intensified after it appears one of the largest exchange websites went offline due to a crippling theft. The Tokyo-based Mt. Gox site only returned a blank page on Tuesday after reportedly suffering from a massive loss of Bitcoins. This follows the Sunday resignation of Mt. Gox CEO Mark Karpele. The company internally issued a “Crisis Strategy” report, which claimed 740,000 Bitcoins were missing, which equates to $350 million at its current exchange rate. The theft apparently went unnoticed for several years, and a single Bitcoin's value has fallen from $550 to $470 in just a matter of hours.