[drdaeman]

This is correct, but the whole thing is marketed as email address, so it will be used as an email address, i.e. means of contacting me.

Now, consider I want to try some service I don't trust. I sign in with a email-looking identifier (which doesn't work as email address) and use the site for some time. Eventually, I become fond of this service and want it to start contacting me. With 123done.org I can't do this, nor at the mineshafter.info, nor at crossword.thetimes.co.uk. Trovebox looks broken to me, so can't tell it works, and I was lucky with voo.st, as it allowed me to add more accounts. Don't know more sites using Persona. Considering, today when you register with only Facebook or Google account relatively many sites don't let you change that binding in the future, it's very likely the situation with Persona will be the same.

[Groxx]

Hopefully, the existence / use of non-emailable browserid providers would encourage sites to accept alternate / custom 'primary' email addresses. It's definitely a chicken-and-egg problem though, and far from guaranteed that it would be resolved happily. And I'm in complete agreement on the marketing, and it's a problem for this setup - the system is young though, maybe this can be changed.

Though honestly I suspect browserid would encourage this anyway, since people are likely to use their primary email address, and they are likely to change to a different address in the future. If sites want to keep people through such a change, they'll want to allow changing it (since I doubt I'm alone in resenting sites that require me to maintain an address I don't use. resentment isn't good for retention).

[drdaeman]

Found out that Persona team do encourage this: https://developer.mozilla.org/en-US/docs/Persona/The_impleme...

Personally, I wouldn't call email addresses identities, and just say they're credentials. But Mozilla clearly has another idea on what the identity is.