Open source software is about collaboration (more eyeballs checking that code!). Wikis are all about collaboration. So it'll come to no surprise that we try to leverage existing technologies and partner with others instead of reinventing the wheel.
Tiki partners with the following technologies:
DHTML Calendar
FeedCreator
Graphviz
Graphviz is open source graph visualization software.
HAWHAW
jQuery
jQuery is a fast and concise JavaScript Library that simplifies HTML document traversing, event handling, animating, and Ajax interactions for rapid web development.
Morcego
Morcego is a 3D graph browser that allows users to view and navigate any graph-like structure. Examples: social networks, site maps, hierarchy or genealogy trees, etc.
PHP
PHP is a widely-used general-purpose scripting language that is especially suited for Web development and can be embedded into HTML.
phpCAS
phpCAS is a simple interface to Central Authentication Service for PHP web applications.
Smarty
Smarty is a template engine for PHP. More specifically, it facilitates a manageable way to separate application logic and content from its presentation.
SouceForge.net
Zend Framework
Extending the art & spirit of PHP, Zend Framework is based on simplicity, object-oriented best practices, corporate friendly licensing, and a rigorously tested agile codebase
Please also see: http://mods.tiki.org/