What is a CMS?
CMS stands for Content Management System: a web application for creating and managing websites. You can check it on Wikipedia:CMS
Why use a CMS?
Here is a simple comparison between CMS and Custom Websites:
Ease of Use: CMS make it easier for people with little or no technical skills to create and edit web pages. While with custom websites, they will need to know HTML, CSS and sometimes Javascript and some programming languages such as PHP or ASP.
Extensibility: adding new functionality to your website is easier and faster by using CMS modules and plugins, while it has to be coded from scratch with custom websites, most of the times.
Flexibility: Custom websites might have more flexibility and you can modify the code without worrying about the CMS limitations. Although with open source CMS, such as Joomla or Drupal, you can workaround these limitations most of the times.
Changing Design: in a good CMS, content is separate from design, and I can change the design with a click of a button. This is much harder with a custom website, even if the custom site is completly CSS based.
Time: custom websites take more time to build than a CMS.
For example, adding a membership section to the Women in Technology Lebanon website is a matter of minutes, or couple of hours if some advanced configuration and customization should be made. While adding a membership section on a custom built website, will require that you know html, css, and be able to create and configure a database.
I strongly believe and recommend that every website should use a CMS, even for tech savvy people.
What do you think?