I'm still having the problem with the preview function. I'm using Firefox 18.104.22.168 on Windows XP and it happens regardless of topic, length or content – flattery, sarcasm, dumb puns, even buying drinks. I see the loading wheel spinning, but it never actually loads. If I stop it, I lose everything I've written.
Maybe it thinks I'm so brilliant I should post directly without second thought, but I doubt it.