A content-management systems, or CMS, is a technology that enables websites to be updated by content specialists who don't want to be bogged down by the technology. A specialist configures the different components, giving the system functionality, wraps it in a pleasing visual presentation and then hands it over to the client. With training/instruction by the specialist, the client is then in charge of the site's content. This separation between the technology and the content enables 'non-techies' to work with the content, safe that their involvement won't break anything.

The content management process is relatively easy. If you can use a word processor or have ever posted a comment on a website, then you can modify the content on your own website using a CMS.

A CMS is also a whole lot more than a system for managing content. It's partly a publishing system that enforces all sorts of careful design rules without an author needing to know anything about how it all works. The key is the separation of the technology from the content. Think of it like a wedding invitation, you are only concerned with the details of the affair, the layout and design have been setup for you.