Open-sourced free content Management System (CMS)Providers

Find below the list of open-sourced free content Management System providers.Personally I have used only Joomla and Worpress. They are pretty good. Since they are used by many people, lot of plug-in/extenstions/mods are available for them.

http://drupal.org/
http://symphony-cms.com/
http://www.joomla.org/
http://wordpress.org/
http://www.boonex.com/dolphin/
http://modxcms.com/
http://www.jaws-project.com/
http://www.impresscms.org/
http://info.tikiwiki.org/
http://www.xoops.org/
http://zikula.org/