Excellent Firefox Plugins and Greasemonkey Scripts for September, 2008

Here is my current list of Firefox Plugins and Greasemonkey Scripts. If there are some essential ones I have missed, please add them in the comments below. Students of mine have as mandatory the items labelled -s-. Browsers Firefox -s- Flock Opera Seamonkey Of the following extensions, all work in Firefox, and many (most) work [...]