BuiltWith [1] is a website analysis tool, providing technical analysis and SEO optimization information to further your website's marketing, sales and navigation effectiveness.
This is an interesting online tool that allows users to do an audit of their own site or other sites of interest to see how well it does on SEO. Not only that but it also provide useful information such as which CMS is powering the site and what type of web server with extensions and technology the site is using.
Last month, they have added another web services called Open Calais [2] to BuiltWith.com. Open Calais is a web service that provides semantic meta data information.
I'm not sure how accurate the information it provides is but it was interesting and fun to try it out. Give it a go and see how well your site rates. Could be time to really have a look at your own site again, under the hood... :P
Link: Built With [1]
Links:
[1] http://www.builtwith.com/
[2] http://www.opencalais.com/
[3] http://duvien.com/node/74
[4] http://duvien.com/node/78