Previously it was possible to get the facebook user id associated to an email by polling the api:
$facebook->api('/search?q=' . $email . '&type=user');
or via url:
https://graph.facebook.com/search?q=mailbox@example.com&type=user
The last time it worked for me was october 28th. Now an empty result is returned. Searching by anything else still works.
Did anything in the API change or is facebook now blocking email searches? I'm using the latest (3.1.1) PHP SDK and OAuth 2.0;