I'm redesigning a website for a client, who wants it to be more friendly for visitors with disabilities. This addon helps me test my code for screwups ("bulletone.gif, bullettwo.gif, bulletthree"... arg!) and saves a lot of headache!
Peter, I have a hidden disability and use Kurzweil 3000 to read all text documents. I also used Kurzweil to read the web, but I couldn't get the program to work consistently after Firefox 4.0. I would end up copy/pasting from the Firefox to Kurzweil, and it was very labor intensive. Thanks to your add-on, now it is much easier to get Kurzweil 3000 to work with Firefox 17.0.1.
Great tool to use in working towards ensuring section 508 (http://www.section508.gov/) compliance of a web page. For the newest version (firefox 3 compliant) check their site (http://www.standards-schmandards.com/projects/fangs/).