dropdown-componentsComponents are the primary functional units of Joomla. Joomla.org refers to them as mini-applications.

The Components dropdown menu will give you a list of the Components that are installed on your site. A number of core components come installed with the initial Joomla 3 installation, but as you add 3rd Party Extensions to your site, you will see this list grow.

As an example, if you install JCE Editor, a 3rd party Text Editor that adds many additional features for the TinyMCE Text Editor, you will see JCE Editor in your list of Components.

Different Components will have different features in their pages in the Component section.  Some will just have settings options and permission options, others have you create content within these pages. Different Components will do very different things and by installing Joomla Extensions, you can have Components that greatly expand the functionality of your site.

Default Joomla Components

Banners: allows you to organize advertisements on your site and will keep track of impressions and click-throughs

Contacts: this component allows you to create and organize Contact information for your site, for employees, for contributors, for departments, etc.  You can then display this Contact information in various ways with a Menu Item.

Joomla! Update: Will check for Joomla updates.  This may or may not be allowed in your hosting environment.

Messaging component allows you to send email messages to different User Groups.

Redirect will allow you to create redirect for pages that you have renamed or removed so that if a Search Engine has the old name indexed, you can send the visitor directly to the new page. There are plans to remove the redirect component from future Joomla releases. I would be better to install an extension for this functionality or use your .htaccess file.

Search: This is the really basic Search function of Joomla that dates back to its earliest versions. It does not have the functionally or options of Smart Search.

Smart Search requires that you enable the Plug-in in the Plug-in manager under Extensions, then will index all the content on your site. A large site can take quite some time to index.

Weblinks: This will allow you to create links to outside sites, organize them, update them all in one location. You can then add those links directly into an Article.  If a link changes, you can change it in one place rather than have broken links all over your site that you didn't catch. The weblinks component has been removed from the standard Joomla installation beginning with 3.4. If you have upgraded your Joomla site from an earlier version, the weblinks component will still be in the component dropdown list. If you installed a fresh 3.4+ installation. the Weblink component will not be present. If you wish, you can install a weblinks extension for this functionality.