ErfurtWiki

This is a WikiWikiWeb engine implemented in the PHP web scripting language. A WikiWiki is a web site which can be edited by everybody who visits it (most commonly without requiring that user to register
before).

It should allow easy integration into an existing web site (portal or homepage / CMS-like software), as it is more a library and does not output a full .html page - but instead just the formatted wiki text for inclusion in your pages` body/content area.

Many extension plugins are available and can easily be hooked in (construction set principle).

ewiki is not just another Wiki engine, it has some features that clearly separate it from other implementations:
- contained within a single file (see the notes on "monsterwiki") 
- does not impose a pre-defined layout, because it integrates nicely into yoursite 
- it is rather fast - uses regexs too, but the formatting kernel
- uses the simple and quick string functions 
- provides case-insensitive Wiki links, multiple database backends, and all extended features are optional (a very exhaustive plugin interface, and over 200 ready to use plugins) 
- highlights: WikiCommander, OpenSearch, WikiSync, PHP-RPC database, PingBack, TextUpload, click-and-run .xpi plugins, image upload, GaGaLinks, XFN, CSS markup, WikiScript (not yet), TCN, and
in-page-macros: TableEditor, WebDAV, ...