I used the new Firefox Live Chat yesterday to resolve a problem I was having with CNN video. There were a couple of hiccups when I had to switch browsers so I could change the Firefox setup. The person I was chatting with was knowledgable and friendly. In the end, she just pointed out a troubleshooting process that I should have known to do in the first place, but sometimes that's just what you need.
Oh, the coComment extension kills the CNN video. I don't know (and don't care to find out) if it is due to a combination of that extension with one of the others I am running, or if it is just because of coComment. I did see other people reporting problems with coComment on AJAX sites so I suspect the extension is just not very well behaved.