The ErfurtWiki engine is fully contained in one script file, but almost 200 feature enriching plugins and extensions modules are available. It follows a library like design and therefore allows rather quick integration into existing web sites (does not enforce a specific page layout from factory page themes/skins).
it has so many feature extensions because of its simple but powerful PlugInterface
it has a very easy ImageUploading function and can cache referenced graphics
works with different database types (MySQL, PostgreSQL, flat file backends, ...)
provides powerful database adminstration tools
besides being very extensible and configurable it is optimized for speed
even allows user defined markup, has extensible CssSupport and is useful as PersonalWiki
it supports multiple platforms
and it has many more differences with other wikis than only being PublicDomain (free as in gift)
Check to see our list of WikisThatUseErfurtWiki and the PublicallyEditableIntermap, ewiki InThePress
some help is also in the OccasionallyAskedQuestions overview
this page in de.
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