Plugins are small task oriented extensions that enhance the Joomla! framework. Some are associated with particular extensions and others, such as editors, are used across all of Joomla!. Most beginning users do not need to change any of the plugins that install with Joomla!.
The search component uses plugins to control which parts of your Joomla! site are searched. You may choose to turn off some areas to improve performance or for other reasons. Many third party Joomla! extensions have search plugins that extend where search takes place.
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System plugins operate every time a page on your site loads. They control such things as your URLS, whether users can check a "remember me" box on the login module, and whether caching is enabled.  New in 1.6 is the redirect plugin that with the redirect component assist you in managing changes in URLs.
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The authentication plugins operate when users login to your site or administrator. The Joomla! authentication is in operation by default but you can enable Gmail or LDAP or install a plugin for a different system. An example is included that may be used to create a new authentication plugin.
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Two new plugins are available in 1.6 but are disabled by default.
Editors are used thoughout Joomla! where content is created. TinyMCE is the default choice in most locations although CodeMirror is used in the template manager. No Editor provides a text box for html content.
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These plugins are behind the buttons found beneath your editor. They only run when an editor plugin runs.
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Content plugins run when specific kinds of pages are loaded. They do things ranging from protecting email addresses from harvesters to creating page breaks.
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