Have you ever been a little curious as to what technologies are used to develop a certain web site? BuiltWith.com answers just that!
Simply enter a URL and BuiltWith will provide information on Analytics and Tracking, Framework, Widgets, Encoding, and anything else they can determine.
BuiltWith.com seems to be fairly accurate, however it stumbles on Classic ASP. Testing Batteries.com proved this.
Overall BuiltWith.com is a fun tool for exploring a little deeper into your favorite sites!