Fully customizable and localizable controllers and views (e.g. Play Authenticate allows you to define your own controllers and views for every visual step of the signup and/or log in process). Completely dynamic URL generation for all views (uses the route file - means you can adapt the look and feel as much as you like). The sample shows how to do this with Twitter bootstrap. Linking of accounts (e.g. one local user with multiple authentication providers). Linking can be done automatically...