I updated Discussion2 again just now. The "Threshold" popup is replaced by a couple of buttons.
The main point of the More/Less and Worse/Better buttons is to help narrow a discussion based on the scores of the comments. This is not very useful in most use Perl; discussions, but you can see it in action in some big discussions.
Also, one thing not mentioned previously, is if you have a long comment so you get the "Read the rest of this comment" link, that will now use AJAX-y goodness to fetch the rest of the comment and load it in-place. Spiffy.