WordPress (WordPress.org) is a content management system (CMS) based on PHP and MySQL that is usually used with the MySQL or MariaDB database servers. WordPress was released on May 27, 2003, by its founders, Matt Mullenweg and Mike Little. WordPress is most associated with blogging (its original purpose when first created) but has evolved to support other types of web content.

Joomla is a free and open-source content management system (CMS) for publishing web content, developed by Open Source Matters, Inc. oomla was the result of a fork of Mambo on August 17, 2005. It is built on a model–view–controller web application framework that can be used independently of the CMS. Joomla is written in PHP, uses object-oriented programming techniques and software design patterns, stores data in a MySQL, MS SQL, or PostgreSQL database, and includes features such as page caching, RSS feeds, printable versions of pages, news flashes, blogs, search, and support for language internationalization.

SubjectsPlus sprang from the loins (more or less) of Pirate Source, developed by the Joyner Library at East Carolina University. It became abandonware, and with permission, an expanded version of this original software was open sourced and renamed SubjectsPlus. Development was undertaken at the Ithaca College Library, and now the University of Miami Libraries. Many people have contributed to SP over the years.