WordPress is a free and open-source content management system and blogging tool. It was launched in 2003 and has since become the most popular blogging system in the world. WordPress can be installed locally on a server or hosted for free on WordPress.com. To install locally, download WordPress, extract to a folder on your server, create a database and user, and run the installation which will generate configuration files. To host for free on WordPress.com, simply sign up and follow the instructions to establish your site online without downloads or installations.