Dear! Modules are those items that are typically aornud the outside of the component (doesn't have to display there, but typically, most of us think inside the box with design and that's where we place modules.) The most important modules are your menus. But, other core modules include the login module or the breadcrumbs or the latest news or most popular news. Modules typically display data, but are a secondary source of information on your page, compared to your component. Plugins are cool little pieces of logic that do something that is not interactive with the site visitor. The plugin that I think is most useful is {loadposition userX} where you can actually place the output from a module (in the example I provided, the modules defined in position userx) right into your article. It's pretty nifty. Other plugins help with system activity or can be used to load videos or format articles in a certain way. Typically, if you get an extension that has components, modules and plugins, you will need to install and configure each of them separately. It might seem a hassle, but I always look at it as an opportunity to see what software capability is really under the hood and consider how I'll use it. A Joomla componentis in fact a separate application being plugged into Joomla CMS. Examples of components are: A forum A newsletter A community system A photo gallery And so on. Think of each of theseas being a separate application. Each one of these would make perfectly good sense as a stand-alone system.Only one component will be shown at any instant in time in the main part of your website. Joomla modules are extensions which present certain pieces of information on your site. It's a way of presenting information that is already present. This can add some new functionality to an application which is already part of your website. A plugin is a script that is triggered by an event . For example, content plugins are run when content is displayed, and usually modifies the output. When an article is opened for editing, the editor plugin runs and displays the WYSIWYG editor that was assigned for that user. Plugins used to be called mambots in Joomla 1.0.x, but since Joomla 1.5.x they're called plugins. Hope that helps!