Firefox addons which are useful for search engine optimization while searching / browsing.

Foxy SEO Tool – Foxy SEO Tool is a free, open source toolbar that provides quick and easy access to a multitude of search engine functions such as Google Site, Yahoo! Site Explorer, Live Fromlinks. Also included are famous web traffic analysis sites such as Alexa, Compete, Quantcast, popular statistic aggregators like Quarkbase and WebSiteOutlook. You can check a site’s listing in important directories like Dmoz and Yahoo! Directory, buzzing Web 2.0 sites such as Technocrati, Wikipedia, Digg, Delicious and links to useful network functions like Whois, Geotool, Internet Archive, etc.

RankQuest SEO Toolbar – This toolbar provides you quick access to more than 30 intuitive SEO tools. Alexa Rank and Page Rank provided by Alexa and Google respectively ensures the popularity of the site. Once you download and install the SEO Toolbar you are only one or two clicks away from carrying out most of your day to day SEO operations.

Niche Watch Tool – This wonderful SEO extension provides you the technical information required to beat your competitor websites in serps.It gives you backlinks number, indexed pages, keyword occurences on the page, page rank, all in anchor, all in title and all in text rank for both domain and webpage information. This cool firefox extension is very useful for webmasters and seo professionals for analyzing niche keyword competition for ranking at top in Google.

Seoquake – Seoquake is a Mozilla Firefox SEO extension aimed primarily at helping web masters who deal with search engine optimization (SEO) and internet promotion of web sites. Seoquake allows to obtain and investigate many important SEO parameters of the internet project under study on the fly, save them for future work, compare them with the results, obtained for other, competitive, projects.

SEO Toolbar – The SEO Toolbar shows PageRank, Alexa Rank, Popularity Index Rank for any website you visit on the one toolbar. Other SEO features include Search Engine view, server header view, Wayback Machine button and links to many SEO forums and websites.

Swoosty SEO Tools – This module, specially created for webmasters who wish to optimize their sites and analyze the concurrence, automatically displays the Google PageRank and Alexa ranking of all the sites you visit, and provides essential tools for complete analysis of a website, which can be very useful if you want to optimize your or if you are looking for new partnerships. In a few clicks you can access a wealth of information such as numbers of indexed pages, back links, related links, the density of keywords, Alexa info, whois data, etc… It can also highlight the nofollow links, in order to avoid making bad link exchanges. The module is very discrete and can be placed at different places in your browser, you can also activate and deactivate it very easily without having to restart Firefox.

SEO Blogger – Whether you blog about business, politics or the hot topic of the moment, SEO Blogger allows you to find the most sought-after keywords for your subject without ever leaving your blog editing screen. The tool sits alongside whatever blog publishing software you’re using so you can do keyword research and optimize your posts as you write. Then, simply hit “Publish” – and you’re done!

SearchStatus – Display the Google PageRank, Alexa rank, Compete ranking and SEOmoz Linkscape mozRank anywhere in your browser, along with fast keyword density analyser, keyword/nofollow highlighting, backward/related links, Alexa info and other SEO tools.

KeywordSpy SEO / PPC Plug-in – The KeywordSpy SEO / PPC Plugin is a Free Mozilla Firefox extension, aimed primarily at helping advertisers, webmasters & SEO analysts to do their PPC & SEO research right from their browser. The revolutionary plugin changes the way advertisers do their keyword research & competitor tracking while browsing on Google & Yahoo in Real-Time.

SenSEO – SenSEO analyzes web pages and tells you how good they fulfill on-page Search Engine Optimization criteria. SenSEO is a Firefox add-on integrated with the popular Firebug web development tool.

SEOpen – This Firefox Addon provides some basic tools to help with search engine optimization. Including google backlinks, yahoo backlinks, PageRank check, http header viewer, and more. All features are available by right-clicking on an open area of a web page, or by using the included toolbar.

SERPAnalytics is a first online SEO environment. It provides variety of SEO tools along with access to database records of essential SEM data, such as dynamics, search engine positions archive and keywords data.

SEO Link Analysis – Enriches the link data in Google Webmaster Tools & Yahoo! Site Explorer by showing the PageRank of the linking page, the anchor text user and whether the link is nofollowed or not.

Live PageRank – Live PR gives you a movable (DnD) widget which shows you the Google Pagerank of the current URL.

DeeperWeb – Boost and Customize Google Search – Easily navigate through Google search results using a fast, simple and useful Tag-Cloud technique. This tool provides Topic-Mapping-Technologies for quick access to answers, news, videos, blogs, Wikipedia and more.

Google Semantics – This tool helps to get synonym for the keyword during your search on Google n which helps for better SEO using Google own Synonyms also refered as Latent Semantic Indexing (LSI) n is a vital element in Search Engine Optimization and article writing