Currently it is the nomination phase of the Ask Ubuntu 2012 community moderator election. I noticed that when you post a comment it is posted as it should but as it is posted the comment remains in the text area. This seems to be a bug. (Comments on questions and answers works as expected for me.)
Here is an example. A comment is entered in text area below a nominee before "Add Comment" is pressed:
After "Add comment" has been pressed and the comment is still in the text area even if it has been posted:
I use Firefox 9.0.1.
Something similar was reported over on Gaming: http://meta.gaming.stackexchange.com/questions/3856/comments-on-nominations-and-other-things-appear-to-be-broken/.