This addon is a gem. Rated 5 out of 5 stars

Why didn't I know this one? It's a real discovery.

I tested the program right on the Mozilla addons pages, and all features actually worked like a charm on my first attempt. If you want to try: when it's installed, click on the new toolbar icon with a W, it brings up a news browser window. Go to Mozilla Addons, do any search that returns several result pages of extensions (I searched for 'video').
The program recognizes that there's a series of result pages and adds several navigation arrows to the traditional ones: the first arrow goes to the next page, the second one automatically browses all result pages, the third digs into all pages and the last one goes up the hierarchy to the site's home page.
Then, you have a series of available views: 'links' gives you all URLs found in the page, 'images' gives you all pictures with their size and info, 'emails' is empty as the page doesn't contain any, 'tables' dosen't contain much in this case, 'lists' is more interesting but the 'guess' view is pretty amazing: it somehow extracts a well-formed list of all the extensions of the page that you can automatically move to the collection basket or directly export to Excel. Then I went to Yahoo, looked for 'sunset' images, it directly grabs the hi-resolution images and you can view the whole search result (hundreds or thousands of pictures) as a full screen slideshow in a single click.

All this is just a first impression. There are many features I haven't had time to test yet, but I though it was worth talking about it. That's a great addition to FF3.

This review is for a previous version of the add-on (