Push vs Pull

[Dag Arneson]

Okay, let me see if I have this Push/Pull distinction straight.  Please 
correct me if I'm wrong.

"Pull" protocols are those that put some data out there to be accessible 
via a URL.  The data does not change based on who requests the 
information.  Yadis is such a protocol, since when an Relying Party goes 
to fetch the data, there is no specified way to change the data based on 
who is requesting it.

"Push" protocols are those that allow the user to modify the data based 
on who is requesting it.  OpenID is such a protocol: the data is 
transmitted by redirecting the user between the Relying Party and the 
Identity Provider, and the user can choose to have the Identity Provider 
send his or her authentication information or to cancel the transaction.

Is that right, or is there something I'm missing?