FWIW, a member of the Drupal community has made a pretty sweet Drupal / Mozilla Persona module (http://see.drupalpersona.me/), if you run a Drupal site and don't want to store password-derived data in your database at all.
Not saying that 2factor / persona auth modules aren't the eventual way forward, but the worst thing to do is to run out and do something like adding modules to your site. Installing modules that have any relation to authentication or security should be postponed until a careful review of the code and its consequences can be completed.
