SeoQuake is an Firefox extension which allow you to view statistic of search engines parameters on the fly. SeoQuake for Mozilla Firefox consists of three functional parts: SeoToolbar (requested parameters are shown in a separate toolbar in the browser), Seobar (requested parameters are shown in a separate, fully customizable with CSS, HTML block) and output of requested parameters on Search Engine Result Pages (SERPs).
SeoQuake help so much to do Seo analyze to any websites. It shows me Google PR, Google last cache, some search engine indexes (Google, Yahoo, Bing, Baidu, and Yandex), Alexa rank, Compete rank, Semrush rank, DMoz index, delicious index, digg index, Technorati index, domain age, keyword density, and many more.
See the screenshot below: