A Content Management System (CMS) allows publishing, editing, and modifying content from a central page. CMS platforms like WordPress, Drupal, and Joomla provide easy updates and collaboration for clients. While non-CMS sites are initially cheaper, CMS sites are less expensive long-term and allow clients full control over updates. Popular CMS types include blog-based systems like WordPress and e-commerce systems like Magento and OpenCart. Browser developer tools like Firebug, Chrome, and Safari allow inspecting website code.