The document discusses a lightweight content management system (CMS) called Concrete5. It has goals of easy content editing, previewing content before publishing, supporting quick themes and templates, and having extendable functionality. Concrete5 is an open source CMS with an intuitive editing interface, a small core team but many add-ons, and a short learning curve for both developers and non-technical users. The document provides a timeline of Concrete5 version releases from 2008 to 2011 and outlines its system architecture.