[OpenID] A Case for OpenEmailID

[Martin Atkins]

Here are some facilities offered by HTTP discovery that I think must be 
preserved in other discovery mechanisms for feature parity:

  * Delegation at the whole-identifier level.

Use-case: email redirector services may, as well as forwarding mail to 
your "real" email address, also publish the discovery information 
necessary to delegate OpenID auth to your real email address.

  * Ability to "redirect" (in some sense) to normalize the identifier.

Use-case: Just as with HTTP URLs, there is often more than one way to 
write the same email address. Consumer some.user vs. someuser at GMail, 
for example, or @gmail.com vs. @googlemail.com.