TAG recommends against XRI

"We are not satisfied that XRIs provide functionality not readily available from http: URIs. Accordingly the TAG recommends against taking the XRI specifications forward, or supporting the use of XRIs as identifiers in other specifications"

- Tim Berners-Lee and Stuart Williams, co-chairs, W3C Technical Architecture Group

More details available here...

OpenID 2 added the support for XRIs as Identifiers. XRIs may be used as Identifiers for both end users and OPs, and provide automatic mapping from one or more reassignable i-names to a synonymous persistent Canonical ID that will never be reassigned