I don't think it'll replace Facebook, it'll just be an alternative to it. We've integrated both Persona and Facebook into our site and it works great.
For my business, we need more personal details about each person that we get by default with Facebook (name/age/sex). So, that integration will always be cleaner than Persona because it is just a few clicks.
We've been working with BID/Persona for a while now (we're linked from the /about page) and we're huge fans. If you want to play around with it... https://www.voo.st/
I've seen some preliminary discussions of linking personal information to a Persona and optionally supplying it to the site at login time. If you have a need for that, you should chat with the Persona/BrowserID developers.
It wouldn't be ideal because there would only be a limited number of people who ever took advantage of it. The model for Persona is different than Facebook. Facebook requires this data on account creation and so do we... so we just present the user with a lock out until they give it to us.
Persona could potentially note at login time that you require that information to create an account, and thus require supplying it before attempting to log in.
That said, looking at what your site does, why do you need that information? I can understand why you want it, but what functionality of your site won't function without it?
Yes, we require it. Having the persons name is obvious. For the rest, the site is very specific in its purpose, which is to allow people to register for USA cycling events.
There are some crazy rules around who can enter which race (based on age/sex) and we do our best to help guide people into the right event during registration.
Location is a nice to have so that when we show the list of participants, they can see where each person lives. Future versions of the site will use this information to help people connect with ride sharing to events.
Keeping the UX of asking for this information within our site makes sense when logging in with Persona since it doesn't have the social networking aspects that Facebook has. Most people who are entering bike races won't lie about their age/sex on Facebook (because bike racing is a relatively small community), so generally this information is pretty accurate. Once someone gives us their USA Cycling license number we also validate against the database we have of that information too.
For my business, we need more personal details about each person that we get by default with Facebook (name/age/sex). So, that integration will always be cleaner than Persona because it is just a few clicks.
We've been working with BID/Persona for a while now (we're linked from the /about page) and we're huge fans. If you want to play around with it... https://www.voo.st/