Pairing our devices with our other gadgets have always been a bit of a hassle. Microsoft aims to simplify the process by only requiring that you enter your credentials once, by pairing with a master device, and then have all your other gadgets be automatically authorised.
In the example above, pairing manually with your desktop with automatically also authorize you with your laptop and other desktop also. Extending this, one can see for example the same principle applying to connecting your phone with your Xbox and photo frame also.
In more technical terms, Microsoft claims:
A technique that enables a portable device to be automatically associated with a plurality of computers. Information that a computer can use to authenticate a portable device and establish a trusted relationship prior to creating an association with the portable device is created and stored in a data store that is accessible by a plurality of computers and is associated with a user of the portable device. When a computer discovers such a portable device with which it is not yet associated, the computer can identify a user logged into the computer and use information identifying the user to retrieve authentication information that is device independent and is expected to be presented by the portable device to authenticate it and allow automatic association.
Read the full patent here.