Hello Orbital Shark,
I too have looked at it but not had time to play with it - It is included in 7068 and I think was in 7057, (but may be wrong

).
Seems like it could be useful to have a for people in an enterprise network scenario, although a lot of systems use the eMail address as the user ID in those circumstances due to AD, but it would give a link for alternate ID's.
Think it needs a bit more investigation, and will become more useful if the likes of Google, Yahoo, and the like support it