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

The Component dropdown menu will give you a list of the current Components that are installed on your site. A few 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, you might install JCE Editor, a 3rd party text editor that adds many additional features for the TinyMCE Text Editor. JCE Editor will show up in the dropdown list under 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.

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 wasy 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.

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.

Tags: Tags allow you to group Articles in different ways. Articles can have one or more Tags assigned to them. The Tags can be set to display with the article. When the user clicks on the Tag name, a page with a list of all of the Articles with that Tag will appear. Tag names can also be used to create Menu Items. Tags are similar to Categories, but cannot be used for Category Blogs or Lists in the exact same way.

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.