Also, from a 2001 speech (in which there are a sickenly polite 26 'thank you's!) by Bill Gates:
So today is a milestone for us. It’s the public rollout of these user-centric XML Web services. It is a new model for user-centric computing. This is not the world of cookies and things that are very opaque to users. This is a world of a very explicit schema that you choose how you want to control the different parts of that schema in terms of how you fill in the information and where it is made available.
In addition to control, it seems that Microsoft (or maybe just Bill) saw the transparency of the system to its users as key to its user-centric nature. This wasn't some invisible cookie, but mechanisms that directly and explicitly involved the user in identity transactions. Hints of Infocard.
This principle appears to have evolved into Kim Cameron's "Laws" of 'human integration' and 'consistent experience'.