Like most testers, you probably automate a certain number of websites.. Ever wonder how those websites work? What technologies does that website or blog use? What is the underlying software that the website runs on?
These are all good questions before starting automation on a website and not always easily determined by just viewing a website.
Sitonomy is a cool web service that you can use to get information about a website, such as what technology is used to run the website, what advertising the site uses, the programming language for the website, what kind of server it is running on, and lots more.