May 5th, 2011 
There is wide range of free and paid Search Engine Optimization tools available. Some most popular tools are listed below sorted according by category.
1] Free Firefox Extensions:
- SEO Toolbar – Competitive and search data directly inserted in results obtained by searching.
- Rank Checker – It tracks rankings easily and automatically on all important search engines.
2] Free Web based SEO Tools:
- Keyword Suggestion Tools – By this tool, you can get keyword suggestions and the detailed statistics.
- Keyword List Generator – This tool is used to compare keyword lists against each other.
- Keyword List Cleaner – It simply cleans your keyword lists.
- Meta tag Generator – It generates Meta tags for your web page.
- Server Header Checker – It verifies that your server is sending the correct headers or not.
- Link Suggestion Tool – It suggests keywords to search for to find relevant link sources.
- Spider Test Tool – By this tool you can view your web page like a search engine spider.
- Keyword Density Analyzer – It analyzes the keyword density of your page as well as competing pages.
- Page Comparison Tool – It compares your page with competing pages to find keywords.
- Ad Group Generator – Generates ad groups to upload to AdWords and AdCenter.
3] Premium Firefox Extensions:
- Website Health Check – It quickly checks for many common SEO issues.
- Duplicate Content Checker – Find pages that contain sentences matching your content.
4] Premium SEO Tools:
- Local Rank – Links to top ranked Google pages from other top ranked results.
- Hub Finder – It finds pages that link to competing sites which are likely to link to your site.
- Competitive Research – It is used to find out where your competitor’s are succeeding in search.
- Domain Name Finder – It gets keyword suggestions and finds associated domain names.
- SEO site Planner – Plan out your SEO strategy from beginning to end.
- Keyword List Comparison – Use this tool to compare keyword lists against each other.
