Have you ever wondered what technologies Facebook is using in order to give users, best social networking experience or what are the services that YouTube utilizes behind the scene that gives you seamless video streaming experience? Well, this information is not publicly available; however, there are web services available that can detect the technologies and services being used by a website. This article presents a brief overview of such websites.
Builtwith.com is the best website that provides technology insight into other websites. It has a simple landing page where user enters the name of the website and all the technological details of the website are displayed to the user.

Similartech is another website that contains detailed information about technologies that are currently being used by different websites. Apart from containing information about the individual websites, Similartech also provide overall statistics about a certain technology. For instance, the landing page of similartech contains information that PayPal is being used by 905526 companies.