Builtwith is great on line tool which can give you details about every single technology that powers some website. Just enter URL of any web site you want to check, press Lookup button and in few seconds you will have full report. Builtwith will return all the technologies it can find on the page.

BuiltWith technology tracking includes widgets (snap preview), analytics (Google, Nielsen), frameworks (.NET, Java), publishing (WordPress, Blogger), advertising (DoubleClick, AdSense), CDNs (Amazon S3, Limelight), standards (XHTML,RSS), hosting software (Apache, IIS, CentOS, Debian)…