I understand what OAuth does...more or less.  I would predict that my sister does not.  &quot;Google&quot; and &quot;Facebook&quot; don&#x27;t connote privacy. They imply that if a person types &quot;shoes&quot;, the next four hours of browsing will be full of shoe ads. That&#x27;s the dissonance.<p>Why have a login at all?<p>Login is clearly aligned with privacy when &quot;privacy&quot; is mostly defined in terms of authorization. Login is less aligned with privacy when it is defined in terms of anonymity.<p>Google+ and Facebook are both services built on removing anonymity.