From what I can tell, the goal is to make the experience easier on the user by doing the email domain to URL transparent.
The reality is that users don't know URLs as identification mechanisms. They do know email addresses.
The reality is that users don't know URLs as identification mechanisms. They do know email addresses.
Users are comfortable using an e-mail address as an identity. Everyone has an e-mail address. This makes sense to end-users.
E-mail addresses are unique and they accurately identify who someone is. I have no idea why this wasn't the standard in the first place.
If every service simply required an email address, and the standard provided for a way to find out the access point from the OpenID provider, then we'd be all set and everyone would be able to implement this change.
The URL is simply a pointer to my identity, which is all I should have to give. The different formats the providers use is what makes it confusing (example.com, username.example.com, example.com/username, and now username@example.com)
It seems most OpenID implementations handle identifiers without the http:// prepended.
If the libraries don't already support the "@" syntax, they should.
If Google's way of doing things requires any proprietary changes, I'd say it's unacceptable, but if that's the only change necessary then it seems like a reasonable way of doing things.