The website you quote says:
A proof of residence dated within six months for the address indicated on the application. (PO Boxes are not acceptable.)
Please note that we are unable to accept any statement or bill that has not been received in its entirety. Information such as the billing name and address must be visible, as well as the company that has issued the bill. Your document must not be folded. Payment stubs are not acceptable, as they display limited information. Confidential information, such as an account number(s), may be removed at your own discretion.
Examples of this include a:
• Gas bill• Electric bill• Telephone bill• Mortgage bill• Credit card statement• Bank statement• Current lease agreement
See, they explicitly accept bank statements, while MtGox doesn't, which makes it impossible to verify for a whole lot of people who don't own or lease any house where they pay bills. Actually probably more then half of the worlds population will not be able to satisfy MtGox requirements, look: at every house usually several people live, and only one of them pays the bills. And the rest? Are out of luck for MtGox accounts... I've seen no other financial institution which doesn't accept bank statements for that purpose.