This document discusses multi-tenanted content management systems (CMS) where a single installation of software can be used to power multiple separate websites or domains. Key points include that each site has its own configuration file detailing database and theme settings. Maintaining a single codebase is cheaper and easier than separate installations. Popular CMS like Drupal, Joomla and WordPress have built-in or plugin support for multi-tenancy. Configuration files can be stored in a database or file system. Requests are routed through a proxy to determine the actual file locations based on domain.