Apache is a free and open-source cross-platform web server software.
PHP is a general-purpose scripting language used for web development.
Unix is a family of multitasking, multiuser computer operating systems.
vBulletin is tool that is used to create and manage online forums or discussion boards. It is written in PHP and uses a MySQL database server.
YUI is a JavaScript and CSS library with more than 30 unique components including low-level DOM utilities and high-level user-interface widgets.