If you have the "I am willing to help test Slashdot's New Discussion System" checked, you get two cool new features today.
First is that you get a pair of neat CSS/JS sliders in place of the old box with arrows on it. Drag them up and down and you see how many comments are available at each "threshold." Let go and the page updates to match your selection. (This widget is on the lefthand side of the page, covering up text. A horizontal version is coming soon. In the meantime, click the top right corner of the widget to make it go away, if it gets in your way.)
The other is that if a comment is hidden, it is not put into the page, to save on initial page load. The comment is then loaded on demand via Ajax. Slide the sliders to show greater-than-zero hidden comments, then reload to get a new version of the page, then drag the slider back down to reveal the hidden coments. You'll see a "Loading
Of course, none of this serves a big purpose for useperl, with its relatively tiny discussions, but on Slashdot, it should be a huge improvement.