Wordpress is free and open source software that can be used to create robust, multi-user sites. Originally created as a blogging platform, Wordpress now powers nearly 30% of all web sites. It's customizable with a wide variety of plugins that expand its functionality so you can create a site specific to the look and content of your project. This guide focuses on Wordpress.com (takes care of hosting), not Wordpress.org (requires your own server). There are paid plans available at Wordpress.com, but they are not needed to use the software or this guide.