"So like a lot of people you append +name_of_site to your gmail or something? And I think you're right, there is a shortfall in Persona which means that this will be considered a 'new' email address, triggering you to set up a password. However this is a shortfall with _Persona_, which is the shim required because there are no identity providers (or browsers) supporting BrowserID (given your other comments, it seems you haven't understood this). Your problem would be completely solved by 'running your own' identity provider (or your email provider running one) that can deal with the quirk of multiple email addresses resolving to the same identity. Heck, you clearly take so much care in your identity and privacy online that perhaps you would consider running your own identity provider that works with pseudo-email addresses (the protocol doesn't require that addresses are SMTP-routable)? That way you can give sites that use BrowserID/Persona an email address that doesn't resolve to your..." - Jalada