This module is a core of your content. Every website has to have text information, describing your organization, business or even personality. This module can be used to create content of your static pages, or to contain the dynamic content of your website, like news, thematical articles, blogs etc.
The module can be connected to other "simplier" modules to use pictures from the Image module, to use videos from Video module etc. If you want to start to get familiar with your way arounde Cornerstone - this is a module to start with.