Now that bug 9587 has been pushed up into the master branch of the Koha git repository, I’m pleased to say you can use Mozilla Persona to log into a Koha public interface. It works by using the email address the borrower has set as their primary email to match a borrower to the user logged into Persona. Since applications like Drupal and Mahara also support Persona you can implement a simple single sign on solution with very minimal effort. But the main win is we allow borrowers to login without needing to remember yet another username and password.