Joomla is a Content Management System (CMS). CMSes are intended to remove the tasks of managing a website from the task of managing the content.

The purpose of any website is to provide information (content) on the web. Simple idea, not so simple to implement. When the web first started, the only way to do this was to learn HTML, figure out how the website was going to look, how to publish HTML pages and then start putting together the content. It took some rather technical folks to do this. Sometimes the content was generated by a non-technical person but it still had to be handed to a technical person to be posted to the web. This added a requirement for there alway to be a technical person some where in the loop to post anything to the web.