WordPress is free software that can be used to create a website or blog. It originated in 2003 simply as code that enhanced typography and has evolved into the largest self-hosted blogging platform in the world.
WordPress is an open-source software, meaning that there are developers who contribute to enhancing it and that anyone can use it without paying a licensing fee. The software can be downloaded and installed on a Web host and customized however the user wishes through plugins, widgets and themes in order to create anything from a blog to a sophisticated content-management system. There is also a WordPress service available to create blogs that are not self-hosted, but it is less flexible than the customizable version.