Heard of this a couple of times, never bothered to check what it did though, until today. It’s the best thing ever! Firefox is so much better with it, and I love it.

First, go and install the plugin, then install some good scripts.

If you’re a Gmail user, this one is invaluable. And this one puts the contents of the alt="" attribute into a tooltip, so you can see the “alt” text of an image just like you used to be able to in IE!