Identity is something that can be seen public. Authentication is a way of proving that you are "the" person who is supposed to get the access to the system. Whe

Identity is something that can be seen public. Authentication is a way of proving that you are "the" person who is supposed to get the access to the system. When your identity is stolen in a system where identity is equated with authentication, you are the one who is responsible for "thefts" actions. Users can be held responsible for their actions only when identity and authentication are kept separate. An article that explains this point in more detail: http://technet.microsoft.com/en-us/library/cc512578.aspx http://technet.microsoft.com/en-us/library/cc512578.aspx