Say I've successfully authenticated a user. How do I get her guid? 

Using, for example, the Facebook API there's graph.facebook.com/me. Is there something equivalent for Yahoo?

I know tere's the http://social.yahooapis.com/v1/user/blah/profile endpoint but at this point I'm not sure where I would get "blah" from.

<div style="padding-top:7px;padding-right:7px;padding-bottom:7px;padding-left:7px;font:normal normal normal 13px/1.22 arial, helvetica, clean, sans-serif;">The answer for this (and probably the forum posts below): &quot;introspective GUID&quot;<br><br><div style="padding-top:7px;padding-right:7px;padding-bottom:7px;padding-left:7px;font:normal normal normal 13px/1.22 arial, helvetica, clean, sans-serif;">hxxp://developer.yahoo.com/social/rest_api_guide/introspective-guid-resource.html<div style="padding-top:7px;padding-right:7px;padding-bottom:7px;padding-left:7px;font:normal normal normal 13px/1.22 arial, helvetica, clean, sans-serif;"><br><div style="padding-top:7px;padding-right:7px;padding-bottom:7px;padding-left:7px;font:normal normal normal 13px/1.22 arial, helvetica, clean, sans-serif;">hxxp://developer.yahoo.com/forum/OAuth/Auto-Login/1294033201000-e35fca11-c1ae-31b4-aa26-b6341e872719<div style="padding-top:7px;padding-right:7px;padding-bottom:7px;padding-left:7px;font:normal normal normal 13px/1.22 arial, helvetica, clean, sans-serif;">hxxp://developer.yahoo.com/forum/OAuth/How-to-get-Yahoo-Id-with-Oauth/1320206452634-0520691e-74dc-4baf-8868-e137cb7d0d8e<div style="padding-top:7px;padding-right:7px;padding-bottom:7px;padding-left:7px;font:normal normal normal 13px/1.22 arial, helvetica, clean, sans-serif;">hxxp://developer.yahoo.com/forum/OAuth/Getting-Yahoo-user-email-address-using/1322497590110-d776ee65-c0e3-4ec3-a2c3-44ab7fa91ce1<div style="padding-top:7px;padding-right:7px;padding-bottom:7px;padding-left:7px;font:normal normal normal 13px/1.22 arial, helvetica, clean, sans-serif;">hxxp://developer.yahoo.com/forum/Contacts/How-to-retrieve-User-GUID-/1275774962000-b07496cb-a138-3ab6-a74a-4c143a9c7168</div></div></div></div></div></div></div>