Everything about a Website
Quarkbase is a free tool to find complete information about a website

Le Top des Blogs réalise des classements des blogs francophones et permet d'accéder gratuitement et simplement aux statistiques publiques d'un blog: trafic, pagerank, classements, fréquentation, publications, ...

 Website Analysis and SEO Optimization
Web technology information profiler tool. Find out what a site is using.

Free SEO tool from HubSpot that provides an Internet Marketing Report for your website.

 Walk. Explore. Have fun ;-)

The biValidator, this website helps you check the markup and style validity of your pages on the same time.