A content management system (CMS) is a web-based software that allows users to build and manage content on their websites. The best CMS for a website depends on its purpose, size, and user's skill level. WordPress.org is the most popular and user-friendly CMS, ideal for small to medium-sized websites, while Drupal is better suited for high-traffic websites. Ghost is perfect for bloggers, ButterCMS offers a headless CMS solution, Grav is a lightweight flat-file CMS, Webflow is a website builder with an integrated CMS platform, Squarespace allows users to build and manage websites quickly, PageKit has a modular design, Textpattern provides flexibility and customization options. Ultimately, the right CMS depends on the user's needs and skill level, and automation can be achieved through integrations with Zapier or other services.