In simple terms data caching is storing data in memory for quick access. Typically information that is costly to obtain (in terms of performance) is stored in the cache. One of the more common items stored in a cache in a Web application environment is commonly displayed database values; by caching such information, rather than relying on repeated database calls, the demand on the Web server and database server's system resources are decreased and the Web application's scalability increased. As Microsoft eloquently puts it, "Caching is a technique widely used in computing to increase performance by keeping frequently accessed or expensive data in memory. In the context of a Web application, caching is used to retain pages or data across HTTP requests and reuse them without the expense of recreating them."