Today, a variety of services use server-side scripting to deliver results back to a client as a paid or free service. An example would be WolframAlpha, which is a computational knowledge engine that computes results outside the clients environment and returns the computed result back. A more commonly used service is Google's proprietary search engine, which searches millions of cached results related to the user specified keyword and returns an ordered list of links back to the client. Apple's Siri application also employs server-side scripting outside of a web application. The application takes an input, computes a result, and returns the result back to the client.