Well, when discussing impersonation we are not very far away from global internet authentication. I found this great presentation on how identification probably will work on the Internet in the future. It deals with webservices and CRM:s (Salesforce.com acctually). Above being a very interesting presentation concerning facts, the presentation technique is quite unique – check it out!
Gustaf Westerlund
CRM and SharePoint Consultant
Humandata AB
www.humandata.se
Nice thoughts on impersonation… I will check the link you suggested…