These tools are great at giving a quick glance at how your Web site functions and how it could be improved. Some of my other favorites like this are Web site Grader, Compete, and SEM Rush.
What is it used for?
SpyFu is good at looking at organic search result rankings and paid search campaigns for competitors and your own site.
What is it used for?
Submit Express is good for quickly looking at meta data, link popularity and html. It also has measures in place to determine how relevant keywords and descriptions are for each page.
For your keyword research try using KeywordSpy – a keyword research technology that will help you know what keywords your competitors are using and how it generates money for them, you can use those keywords to drive traffic to your site and give your business the exposure it needs. It offers Free trials.
It goes with a ClickBank Affiliates Search Engine where you can see the actual market landscape at ClickBank.