The Discussion 2 system breaks under the comment load in the "Putting Anti-Evolution Candidates On The Spot" discussion at http://ask.slashdot.org/article.pl?sid=07/08/17/1939200. That page is *extremely* slow to load (taking 15-20 seconds rather than the usual < 1 second on my Core 2 Duo 6600 system) and the scroll wheel no longer scrolls the page but rather shrinks / zooms the display font in Firefox 2.0.0.6 on Windows XP Professional. Display in general is very sluggish, and CPU load is non-zero probably due to the amount of javascript being executed.
Discussion 2 works fine in every other story I've read over the past few months, so I believe that the broken behavior is triggered by the unusually large number of comments in that story.