Whilst I understand and really like the non-tied in aspect of it, I'd probably implement some sort of facebook/twitter/google account authentication alongside of it.
Reason being is that, it too is just another authentication service that I'd rather users not have to make the effort to sign up for.
The intention seems to be that browserid.org is temporary, just there so that this can work until it's supported by browsers and identity providers directly. Once that is achieved, there's nothing extra to sign up for.
Reason being is that, it too is just another authentication service that I'd rather users not have to make the effort to sign up for.