Its a WordPress Cache plugin that can creates static html information out of your dynamic WordPress weblog. When a web page is rendered, php and mysql are used. Subsequently system wants RAM and CPU. If many guests come to a website, system makes use of a lot of RAM and CPU so web page is rendered so slowly. On this case, you want a cache system to not render web page time and again. Cache system generates a static html file and saves. Different customers attain to static html web page.