This is the second in our series comparing the basics of Drupal and Joomla. As mentioned, both Drupal and Joomla have active communities that support the projects and produce add-ons which integrate with them for added functionality. In Drupal, these are called "modules" and in Joomla they are called "extensions" (a term which encompasses three sub-types: components, modules and plugins).

Drupal modules can be anything from complex, feature-rich programs to simple modifications that make one small thing work slightly differently. Joomla breaks their extensions apart into components (usually add-ons which display in the main part of the page), modules (add-ons which display in sidebars and peripheral areas) and plugins (add-ons which run in the background of the system).

Both CMS's have online directories of these user-submitted add-ons which you can browse by category or search for a specific type of feature. If you can't find anything after a thorough search, or if you find multiple add-ons that seem to fulfill your needs, you can also usually solicit advice on the forums from people who may have gone through the same process and have some experience to share.

• Browse Joomla's Extension Directory
• Browse Drupal's Module Listing

Examples of common features provided by modules and extensions:

These examples are just to give you an idea of some of the functionality that can be added to your website quite simply. There are hundreds (or thousands) more, but these are some common ones:

• Forums (in Drupal's core system by default, can be added on to Joomla)
• Features for community sites (user profiles, pictures, directories, etc.)
• Calendars and Events
  
• WYSIWYG editors (Joomla comes with one by default, a variety of editors can be added to both)
• Forms and form controls (custom pages to email information when people submit it and save it in a database)
• Add-ons to extend basic content types and make them more flexible
• Search Engine Friendly URL control or automation (both have some level of this in core and options to extend it with add-ons)
  

Important notes about modules and extensions:

• User-submitted add-ons have not necessarily gone through the same rigorous development process as the core system. You should take care when installing them and ensure that they have a solid base of users and an active community.
• Add-ons generally have periodic security updates and feature upgrades, so you should also make a point of checking back on a regular schedule to see if there is an update. If a security issue is identified, you will want to apply the updated code as soon as possible to prevent a security hole in your website.

Questions? Suggestions?

If you have any particular questions you'd like answered in regard to Drupal and/or Joomla, please leave a comment below and we'll add it to our list of things to post about over the next weeks or months.

*Note: Joomla "plugins" were refered to as "mambots" in Joomla 1.0.