Typically, a Content Management consists of a minimum of three elements: the Content Management Application (CMA), the Meta-content Management Application (MMA), and the Content Delivery Application (CDA). Some Content management systems have more elements like portals but the Content Management will rely on these three.
CMA manages the content components (like text, images, links, graphs etc.) of the CMS. MMA manages the information about the content components.
CDA provides a way of displaying content components to the user of the web site.
CMA manages the full lifecycle of content components, from inception through archiving. A CMA will create, maintain, and remove content components to and from a repository. The repository can be a database, a set of files, or a combination of both. The management process is sequential in nature and is usually accomplished using a workflow management solution of some sort.
MMA is an application that manages the full lifecycle of meta-content. Meta-content is the information about the content components, in particular how the layout on a web site and descriptive tags. The purpose of the MMA is to progress meta-content through its life cycle. The process closely resembles that of the CMA but with a completely different focus: the generation of meta-content.
CDA combines the content components out of the CMS repository and meta-content from the MMA to generate web site elements. CMS usually only install and configure the CDA since it feeds off the data you created within the CMA and the MMA.
CDA may have several forms of publication to ensure scalability and availability.