[OpenID] Yahoo hijacking?

[SitG Admin]

>If potential adopting sites come to believe that there's a 
>non-negligible chance that sending someone off to signin with OpenID 
>is the last time they'll see them, and in this case that on the 
>margin, the IDP is potentially competing with the RP for the users 
>attention, we're in trouble.

I need clarification on one point here - what role are these 
"potential adopting sites" playing? Are they sending the user off to 
a 3rd-party IDP to sign in to the adopting site, or are they letting 
the user sign in to a 3rd-party RP by providing the OpenID 
credentials? I need to nail down some concretes before I can 
generalize; I need to have something solid to generalize *from*. Does 
this sort of scenario revolve around becoming an IDP or becoming a RP?

-Shade