An open protocol to allow standard email addresses to be transformed into URLs for services like OpenID.
One of the greatest advantages of using URLs as identifiers for individuals is the ability to "hang" additional services off of that URL. A user can specify which authentication provider they use, which contact service, etc. Perhaps the greatest disadvantage of URLs, as we've learned in the early years of OpenID, is that users are simply not accustomed to using them as identifiers for themselves. Email addresses on the other hand, have been used as user identifiers for some time. The Email Address to URL Translation specification defines a method to convert users' email addresses to URLs for use in services such as OpenID authentication.
EAUT is designed to work in a distributed fashion, so that no one authority controls it. Every email provider can control how email addresses at their domain are resolved into URLs.
While EAUT is designed to be completely decentralized, it will take some time for email providers to add support. In these cases, a fallback service can be used which can transalte ANY email address to an URL. Relying parties can use any fallback service they wish, but Email to ID is recommended. The need for any fallback service will diminish as email providers begin to support EAUT natively.