A Content Management System (CMS) is a type of website with a user interface, much like any webmail, so it is possible for clients to add pages, change content and do a number of things to their website without a webmaster’s help, or any knowledge of HTML. The learning curve is quite simple.
Some of the most popular open source CMS’s are WordPress, Drupal, and Joomla. Most webmasters are familiar with them, so you won’t be forced to stay with any particular webmaster or web design company because they used proprietary code. See Tips on choosing the right webmaster for more information.
Things to Know
Most CMS’s are database-driven, so you must have a hosting account with a database. It is usually simple to have one added to an existing hosting account if applicable.
Also, new versions come out, and your site will need to be updated periodically, or it can risk being hacked. It can be fairly simple for a client to update some CMS’s themselves, though the new version will have to be compatible with any plugins or extensions on the site, so it is advised to have a webmaster do it so you don’t risk breaking something on the site. This topic is covered in Why Website Maintenance?