There seems to be some performance issues going on - the active tabs/main pages are empty, things are intermittently loading and not loading, and.. well.. the sites arn't running like clockwork like they usually do. I'm seeing blank front pages here, SU, SF and on Ask Ubuntu at least.
I'm aware of this but the issue seems different, more widespread and the other one is fixed, so it can't be the same bug, can it?
EDIT: Apparently SE has version numbers! Mine say
rev 2012.11.2.271 If a site's non worky might help to check that. It seems to be working for me now