Federated identity "mashup" demo, using multiple protocols for signing up and participating in a medical device trial

I came across this interesting identity "mashup" demo, after seeing it highlighted by Kim Cameron on his Identity Blog last month. From the original post on the Microsoft Developer network:

Medtronic, PayPal, and Microsoft worked together to produce a multi-protocol federated identity “mash-up” demo using multiple protocols (OpenID and WS-Federation). This demo was shown at the Internet Identity Workshop and to members of the IEC Council.  The demo shows how Medtronic customers could use PayPal identities when signing up for and participating in a medical device trial.

The attached diagram explains this better. The diagram is taken from this blog post by one of the developers, where he says: 

[..] We called it an “identity mash-up” because claims from the PayPal identity are combined with (“mashed-up” with) additional claims added by Medtronic for trial participants to create a composite Medtronic trial identity.  Medtronic creates “shadow” accounts for trial participants, but from the user’s point of view they’re always just using their PayPal account whenever they have to sign for the trial.[..]