WordPress is the most popular open source content management system - a publishing platform that makes it easy to publish content on the Internet. Take a look at sites using WordPress at http://wordpress.org/showcase/ and at Notable WordPress Users.
You can download a copy from http://wordpress.org or you can set up a free account at http://wordpress.com and just play with it to learn how it works. Not all features are available from wordpress.com.
OpenSourceCMS.com has a demo for hundreds of content management systems at the following link: http://www.opensourcecms.com. This site allows all visitors to act as the administrator of all the different demo CMS installations they list, and it gives you an opportunity to try each of them out before you take the time to download and install. The demo sites automatically reset themselves to the default installation each hour since everyone has administrator access.
WordPress has built-in features that connect to a MySQL database on the server allowing users to create data driven Websites without having to code anything. Web developers can create custom code, but anyone can use it without coding. Check out http://wordpress.org/about/features/ to see all the features and benefits of using WordPress. Here are a few built-in features you get with WordPress:
- User Registration - visitors can set up accounts
- Remote Updates - multiple people can update content from Web interface
- Blogs - built-in blogging software
- Themes - hundres of WordPress themes are available to control look of a WordPress site
- Plugins - can extend WordPress to do almost anything you can imagine. Over 28,000 plugins at http://wordpress.org/plugins/
- RSS Feeds - can be used to populate your site with content
- Documentation - complete documentation at http://codex.wordpress.org
Check out the videos from Word Camp at WordPress TV.
You can even use WordPress as a content management system - check out How to Use WordPress as a Content Management System
Write your own PHP code to create your own WordPress Plugin, or use any of the Free WordPress Plugins.