[OpenID] About Facebook, MySpace and OpenID

[SitG Admin]

>'if_available' suggests if the OP happens to know it, then the RP 
>wants it.  This isn't a 'if_user_opts_in' parameter.  Which makes it 
>basically the same as 'required', except the OP can feel less badly 
>about not supplying it.

This may be an attempt at convenience for the user. When the RP 
doesn't know how many of its "optional" fields a user may want to 
fill out, it can't guess which ones to put as "required" so the OP 
will respond - and the RP doesn't want to pose an inconvenience upon 
the user to type in fields manually just because the user wasn't 
asked for them originally.

That's how I thought AX *worked*, or was supposed to: the user could 
click on "fill out this data automatically from my OP", and the RP 
would send the user back to their OP just long enough to do so.

-Shade