I am creating some eCommerce websites and I would like to undertake a
feasibility study on my competitors. In order to access other
eCommerce websites of the same nature, I would like to know what tools
are available to me to gauage my online competition. For instance;

To see a webpage as the search engines do, running the Keyword Density
Analyzer is helpful;

- KeyWord Density: http://www.searchengineworld.com/cgi-bin/kwda.cgi
- Google Pagerank provides a rough ranking of a webpage
- Google Site Search: Enables me to restrict my search to a specific
website using the site:sampledomain.com syntax in the Google search
box
- Google links: The query link:siteURL shows me the webpages that
point to that specific URL.

I would very much appreciate a list of other helpful tools which would
enable me to analyse my online competitors and indeed, my own website
(www.irishwaterwheels.com).