Forum OpenACS Q&A: Re: Suggestion: Improve the UI with more images, icons, thumbnails...
I think the equivalent of this in Firefox is the FireBug add-on https://addons.mozilla.org/en-US/firefox/addon/1843. Its very cool and has the waterfall Timeline charts and other useful debugging.
Yes, very cool indeed. I've been using YSlow for Firebug for a while, but it's great to have something for IE (as still most of our clients have it as their browser of choice). Nice to see AOL still releasing quality code too.