Joomla is an open source content management system.

So what does that mean?

• Open Source means that anyone can contribute to the code, improve it, or distribute it. This means the platform is a living project being created and improved by a community of developers all over the world.
• A content management system uses a database to place content into designated places on the web page. Its dynamic and in real time.

Let's look at a forum as an example

Joomla works the same way, the template creates "buckets" or "placeholders" for content, and then the CMS pours content into them as needed.

Here, the articles are being dynamically generated as well as the bottom lists of links.

Joomla is

• Easy
• Powerful
• Cheap (not free!)

Barrie North's 80/20 rule

• 80% of what you want to do will take 20% of the effort
• You don’t really know what your site visitors want

Resources

• Official Joomla Project Site
• What is Joomla? (joomla.org)
• What is Joomla? A Website Developer's Perspective (netshinesoftware.com)
• What is Joomla? (joomlashack.com)