wadWiki is a extremely light and simple Wiki engine that anyone can modify. It aims to be a fast scratchpad for arranging ideas without frills and complications. Major releases are supported for more than three years, so server requirements don't get suddenly bumped. Since it is written using only procedural functions, anyone with basic programming skills can adapt it to new requirements. The extension API is stable. There is official hosting for third-party extensions. Because collecting knowledge is not the goal of this project, if you want a full-featured wiki engine, you may wish to choose another software like MediaWiki.