Plugins

One of the more advanced extensions for Joomla! is the plugin (formerly called a mambot). In previous versions plugins were known as mambots. Along with the development of Joomla! 1.5, mambots have been renamed to plugins and their functionality has been expanded. A plugin is a section of code that runs when a pre-defined event happens within Joomla! Editors are plugins, for example, that execute when the Joomla! event "onGetEditorArea" occurs. Using a plugin allows a developer to change the way their code behaves depending upon which plugins are installed to react to an event.

More information on Plugins is available from the Joomla! help manual: Plugins
http://help.joomla.org/content/view/110/153/