Yea maybe I should&#x27;ve been more specific but I was just talking about the user&#x27;s perspective: usernames aren&#x27;t necessary for most sites and just means one more thing they have to create and remember.<p>Re: implementation - I don&#x27;t see the big distinction. These are all just related properties of a master user id number. Those properties can be anything and any of them (in any combination) can be used to login.