It's a content management software. check it out here www.joomla.org It's one of the best CMS out there with hundred of plugins, templates to choose from.
Joomla, its a CMS script (Content Management Script) has very nice features. The templates a remarkable! google // com Search: Joomla =]]!
Joomla is It's a content management software. But you must very cafeul for install this and its add-ons. Some addon has exploit so you should check updates always.
Joomla is a php based content management system, tht allow you to build a content based website without having any knowledge of any serverside script. it is fully customizable. There are other similar applications also like, http://www.drupal.org
Joomla is awesome system to use if you know nothing about HTML, PHP or any other programing language. It takes a bit getting used to it. You also to make it search engine friendly have to purchase addons. I use Drupal (drupal.ogr) it is more search engine friendly out of the box. Also basic Drupal installation comes with addons like adding blogs and forum to integrate in to the website. Read up on both system and then make your decision.
If you're serious about your website expansion, you should try Joomla out. Otherwise stick to wordpress
A helpful thread for me too, i recently decided on becoming a joomla user, seems theres so much available for it.