PHP + MySQL
Ranked in these QuestionsQuestion Ranking
Pro Upgrades are smooth
Because all features of Tiki are supported by core developers, compared to a model where the wiki relies on third-party extensions that may or may not get upgraded along with the core codebase, the upgrades are a lot easier.
Pro Lots of built-in features
Tiki includes tracker, chat, newsletter, forum and much, much more functionality out of the box.
Pro It's a full featured CMS
Tiki supports user-account management, permission management, allows managing menus, customizing layout, etc.
Pro LDAP support
Pro Free and open source
Tiki is licensed under LGPL.
Con Can feel bloated
Since there's so much stuff in Tiki already built-in, it can be overwhelming if all you need is a simple wiki.