Maybe off-topic a bit, because it only handled authentication, but I really miss Mozilla Persona. You just included some javascript in your frontend, maybe a 5

Maybe off-topic a bit, because it only handled authentication, but I really miss Mozilla Persona. You just included some javascript in your frontend, maybe a 5-line function in the backend, and people could authenticate to your web app. No need to store a password and correctly crypt the hash, provide a password change function, provide a password reset function (what a PITA to get correct). Why hasn't anybody created something comparable yet?