WordPress is a free, open-source content management system that allows users to build and manage dynamic websites and blogs. It provides templates called themes that control the visual design and layout of pages. Users can create and edit pages and blog posts called articles directly from their web browser using an easy-to-use control panel. Plugins extend WordPress functionality by adding features like search engine optimization tools. Reasons for using WordPress include the ability to easily update and customize the look and feel of a site using themes, to frequently publish and receive comments on blog posts, and to leverage additional features for search engine optimization and social media.