openid.delegate explained.

[Martin Atkins]

Dick Hardt wrote:
> 
> The RP needs to resolve the identifier to check who is authorative  
> for it.
> 
> If you create a mechanism for how to resolve who owns  
> "mailto:me at mydomain.com", then it works.
> 
> That functionality is needed to prevent any IdP from being  
> authoritative for an arbitrary URI.
> 
> -- Dick

The public URI is still resolvable by the RP as is necessary.

But the RP never uses the openid.delegate value; it simply passes it on 
to the IdP where the IdP can then do what it likes with it. In 
LiveJournal's case, it's simply a regex to see if it matches 
http://([a-z0-9\-]+).livejournal.com/, which could easily be 
mailto:([a-z0-9\-]+)@livejournal.com, or anything else.