Description on Mt.Gox site:The Yubikey is a device allowing secure identification with a "One Time Password". It is recognized as a USB keyboard by your computer, and touching it with your finger causes it to input a 44 characters long password which is unique and can be used only once. Each time you use it a new password is generated, protecting your account even if someone has access to your computer.
You will be able to order your own Yubikey here. The Yubikey will allow you to login to your Mt.Gox account securely via two-factor authentication (you will still need to login with your username and password first).
Please note that our Yubikey can only be used with Mt.Gox.
In case your yubikey is lost, you will be able to order a new one with only your username and password. This will require you to perform no successful login for a few days, and to have enough on your account to buy a new yubikey.
Just want know what you guys think.