Apple has filed a patent application for an improved method to enable user accounts to be portable across different multi-user computer systems. According to the application a user account on a computer can be stored to an external portable data store, making the user account portable. The external portable data store can be an external drive or a media player and hence the user can carry it. The OS on the host computer will be able to locate user accounts on not only local storage of the computer but also in any removable data storage attached to the computer. A user will be able to login to computer and be presented with their user configuration and user directory. In simple words you will be able to carry your user account from your computer to any other computer using an iPod or an iPhone or even a flash drive. All your user data will be saved on the drive basically creating a complete user account. Whenever you attach the drive to a computer that is not your primary computer it will give you an option to log in to your account that is on the external drive/iPod.