Joomla is first and foremost a content management system, which makes it different from both static HTML based designs and those that use cascading style sheets (CSS) to separate web content from style. Joomla uses a 'placeholder' or 'grid' type of system to organise websites, with an information architecture that exists independently from both website content and design. In order to understand how Joomla works, it is important to realise that website content is not actually generated, and in essence does not really exist, until end-users click on the individual links within a Joomla website. This is important from a practical perspective, as it means that Joomla pages can be easily modified by changing individual links without having to change any content at all.

There are two main ways that Joomla generates and organises website content - components and modules. Joomla components are normally the articles, links, and mini-applications in the central part of a Joomla page; modules are often found around the edges of a page. When creating your Joomla website, you have a number of options available as to how you will organise and categorise these individual components and modules, and these decisions will be have a large impact on both site presentation and overall site management.

It is important to understand that the difference between components and modules is in many ways a distinction based on site presentation, whereas the difference between the core Joomla system and any Joomla extensions - which can be components, modules, plug-ins, templates, or languages - is a distinction based on functionality. These two differences are not mutually exclusive, which is the basis of a lot of the confusion surrounding Joomla site management.

Organising Components

Articles and other website components can either be left uncategorised, or categorised in a specific structure using Joomla sections and categories. These three different levels of organisation: sections, categories, and articles, represent the hierarchal structure that is used by Joomla. Understanding the difference between these levels is one of the keys to mastering the Joomla system. Sections represent the top level of the Joomla hierarchy, and can be understood as empty vessels or sets that are used to hold individual content items. A Joomla section acts in many ways like a parent to the individual child categories, where articles and other web content is placed.

Joomla categories represent the next level of website organisation. Categories must always be assigned to specific sections, in a similar way that children need to have specific parents in order to exist. Categories are used to hold individual articles and other content items, and in this way represent the middle tier of the Joomla organisational architecture. Placing articles in an organised and refined category structure is the easiest way to manage a Joomla website, and will have advantages for both end-users and website managers alike. Content can be managed through either the front-end or the back-end of a Joomla website, and the inclusion of a What You See Is What You Get (WYSIWYG) editor makes it very easy to add new content at any time.

The individual articles or other content units represent the lowest level of the Joomla hierarchy, although they are in essence the only level that actually exists from an end-users perspective. Articles must be assigned to Joomla categories, which must in turn be assigned to individual Joomla sections. Content items can not be put directly into sections, making the organisation of categories even more important in the creation of a coherent site structure. The Joomla management system uses a structure that is similar to that used in computer operating systems, with articles (files), placed inside categories (folders), which are in turn placed inside sections (parent folders).

The management of these three differing levels of organisation: sections, categories, and articles, is the key to creating a well organised Joomla website. It is normally best practice to create websites in the same hierarchy that they are organised, by creating sections first, and then following with categories and articles. Sections are created in the Joomla section manager (Content > Section Manager), categories are created in the category manager (Content > Category Manager), and articles are created in the article manager (Content > Article Manager).

Organising Modules

Modules represent the other type of content that is generated by Joomla websites, and while they can be found anywhere on a page, modules are normally seen around the edges of the main body that is presenting website components. While modules can act differently from components, they often work together with specific components in order to provide users with an interactive interface. For example, a log-in module will allow a user to access certain website components that would otherwise be unavailable. Components and modules do not appear that distinctive from the front-end of a website, but they are administered in different ways and need to be managed appropriately from the back-end.

Despite being found on the edges of a page instead of in the middle - and generally a lot smaller in size - Joomla modules do act in a similar way to components. They also provide a specific functionality to a Joomla page, and have a number of presentation options that can be customised to fit the overall page design. There are core modules that come with the default Joomla install, as well as a number of third party modules that can add various features to a Joomla website. Some of the popular third party modules that can be used to extend Joomla include solutions to integrate Google Adsense, and solutions that can add images, audio, video, and scripts to a website.

Joomla modules are one particular type of Joomla extension, which together with certain components, plugins, templates, and languages, are used to extend the functions of a Joomla website. All of these Joomla extensions can be installed from the Joomla extension manager (Extensions > Install/Uninstall), which is able to install from specific packages, native directories, or directly from a website URL. Because modules play a more important role than other extensions do in terms of Joomla content management, they are organised separately through their own sub-menu, which can also be accessed directly through the Extensions menu.

Coherent web design with Joomla requires a well organised selection of modules, as well as a detailed and refined component structure. While no website is ever going to succeed without good original content, a great user interface, or a fantastic design, content architecture is just as important and needs to be addressed from the beginning stages of any new website creation. While the Joomla content management system has the power to easily create professional and well organised websites, it is up to individual webmasters to organise and manage their content in order to make the most of what Joomla has to offer.