SEO for Firefox is something every webmaster shouldnt be working without. What this plugin is it will append various important stats to search results on google. Things like PR, cache, supplmental, alexa rank, etc etc. I use it on a regular basis to help me track important stats for my various sites, instead of some website that most people may goto to find this kind of similar info out. One of the more important recent additions is the supplemental indexing tracker. This has really helped me keep a close eye on the duplicate content some of my sites create, and easily get rid of it. This is definitely a plugin I cant live without now.

Download: SEO for Firefox