Collaborative real-time editing - also called ExtremeWiki'ing or tinging - will make fun explode and will make the all over wikilandia working-speed multiply.
The ting-wiki uses MoonEdit, which is not open source and therefore insufficient. There are two promising and seemingly advanced cross-platform free and open source projects: Gobby and chalks.
the node for different collaborative real-time editor projects is community-wiki: collaborative editor.