> Persona works like email because every identifier is an email address, not an opaque OpenID URL. You don't have to have the NASCAR-esque "Sign in with OpenID Provider X, Y, or Z" login page if users can actually use an identifier that that already know.
OpenID URLs need not be opaque - I use my regular <realname>.com URL as my OpenID, and have a stub in the HTML of /index.html that points to the provider that I want to use when I authenticate (which I can change any time I please). It's called delegation. I think using DNS as an identifier is better than email (as that's kind of what it was built for), but not a viable option for the masses. Mozilla did a good job with Persona.
OpenID URLs need not be opaque - I use my regular <realname>.com URL as my OpenID, and have a stub in the HTML of /index.html that points to the provider that I want to use when I authenticate (which I can change any time I please). It's called delegation. I think using DNS as an identifier is better than email (as that's kind of what it was built for), but not a viable option for the masses. Mozilla did a good job with Persona.