I was under the impression that you needed a web proxy to parse the results of a cross-domain AJAX POST.
But apparently, you can accomplish this with opensocial-jquery.
Could someone please explain how opensocial-jquery makes this happen?
Umm... the very first sentence on the page you linked to explains it
From http://code.google.com/p/opensocial-jquery/wiki/Ajax
All requests generated by jQuery.ajax are relayed to the proxy gadget server. This frees up cross-domain restrictions and maintains compatibility.