Once you've considered the requirements of your CMS and drawn up a short list of required features, it's time to get down to the business of assessing various systems for their suitability. Given the large number of available options, this can be a long and time-consuming task, therefore it's worth considering using a tool such as the CMS Matrix, which allows you to compare the features of different systems side by side.

This approach can be valuable, but with so many systems listed, you still need a place to start. To help with this, we've assessed the features, strengths and weaknesses of five of the most popular and widely-used open source CMS solutions.

Joomla

Joomla is a PHP-based GPL-licensed CMS with powerful features, designed for ease of use. It is primarily aimed at the small business market, but provides professional capabilities and is easily extensible.

• Key features: Large range of built-in applications; comprehensive management tools; WYSIWYG content editing tools; free add-on modules for commerce, multi-language support and multi-site deployment.
  
• Strengths: Easy to use, extend and customize; strong community support; excellent documentation; simple requirements (PHP, MySQL, Apache).
  
• Weaknesses: Some security limitations; content categorization model can be restrictive; somewhat confusing structure.

Official site: http://www.joomla.org/

Exponent

Despite its relative youth, the innovative, PHP-based Exponent CMS aspires to the level of a serious heavy-duty CMS. Its straightforward interface belies the powerful administration, security and content-creation tools that hide below the surface.

• Key features: WYSIWYG content editing tools, comprehensive permissions and user-rights systems; workflow management; peer review and approval.
  
• Strengths: Excellent interface; powerful security management tools; extensibility and theme tools; streamlined architecture and elegant code.
  
• Weaknesses: Shortage of built-in applications; no commerce capabilities; limited functionality of some modules.

Official site: http://www.exponentcms.org/

Drupal

Yet another PHP-based solution, Drupal has a strong following and is widely supported by site building companies due to its ease of implementation and maintenance. Highly recommended.

• Key features: Straightforward web-based installer; support for standard web page development through a web interface; workflow and review tools; strong RSS support; built-in forum and commenting tools.
  
• Strengths: Reliability; support network; quality of code; ease of customization; automatic updates.
  
• Weaknesses: Limited documentation; limited out-of-the-box functionality - many modules are only available as add-ons; poor quality of built-in themes; steep learning curve for customization.

Official site: http://drupal.org/