wiki software
collaborative software that runs a wiki
Apache Wave
software framework for real-time collaborative editing online
BookStack
simple, self-hosted, easy-to-use wiki software
Trac
open-source, Web-based project management and bug tracking system
Confluence
collaboration software
Federated Wiki
wiki engine
Gollum Wiki
wiki system used by the GitHub web hosting system
Fossil
distributed version control system, bug tracking system and wiki server
Jive
the main application produced by Jive Software