Joomla is a Content Management System (CMS). A powerful system sort of like an Operating System for a computer which allows you to install applications.
Joomla is known as one of the best CMS used to develop websites of all kind. Joomla is used to create from simple informational websites to very sophisticated controlled systems.
Developing websites with Joomla is very convenient because it is easy to maintain. Developing websites with Joomla makes it easy to extend and the limit is only to one's imagination.
There are many third party tools that can be used to manage Joomla websites. There are many categories of available extensions such as backups, protection tools, eCommerce and many other advanced applications that allows you to create subscriptions and access levels.
There are also many experts who can help you develop or maintain a Joomla website. You can find experts at www.aztecacity.com