When using an IE browser on my laptop or desktop on this site and trying Facebook Login, the Facebook sign-on "pop-up" is replaced by an empty window, and Q2A does not change to show me as logged on. This gives the impression that login has failed and the site is not working properly. (log-on actually was succesful and if I click on one of the Q2A tabs I am shown as signed in).
This is due to a NEW and "little known" Facebook "bug" where an IE browser with Flash installed (the majority?) is used.
see: http://bugs.developers.facebook.net/show_bug.cgi?id=18405 for details of work round
I added a custom channel file to my trial Q2A and added its uri to the fbinits in qa-facebook-login.php and can confirm it fixes the problem.
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