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).