Schneier on lingering digital wakes ...
This so closely parallels what sucked about subscribing to mailing lists. You just couldn't rely on the vendor's unsubscribe mechanisms, so the world moved on to RSS.
So what's the analog to RSS? And how can it make it into production?
I corresponded with someone that implemented an ldap-based address-subscription service for the Canadian post office. IIRC, companies with your permission could subscribe to an address entered in the service, but you were allowed to revoke this permission whenever you liked. I loved the idea, but I don't know if it made it into production...
Anyway, I would be interested in Bruce's analysis both of solutions to the problem (passport/liberty/sxip/sourceid/onename) and likely introduction vectors given that he's not a big centralized ID fan.