WordPress is an online, open source website creation tool written in PHP. But in non-geek speak, it's probably the easiest and most powerful blogging and website content management system (or CMS) in existence today.
Joomla! is a free and open-source content management system (CMS) for publishing web content. It is built on a MVC framework that can be used independently of the CMS that allows you to build powerful online applications.
Drupal is content management software. It's used to make many of the websites and applications you use every day. Drupal has great standard features, like easy content authoring, reliable performance, and excellent security.
Magento empowers thousands of retailers and brands with the best eCommerce platform and flexible cloud solutions to rapidly innovate and grow.