Loki (short for Logic in Wiki) is a semantic wiki implementation based on strong logical representation.
In the “Loki Family” there are also other projects:
BPwiki – wiki for Business Processes in simpleBPMN notation
SBVRwiki – wiki for authoring rules in SBVR
BiFröST (previously known as PROV plugin) – framework for Collaborative Knowledge Engineering within Loki: automatic reasoning unit tests, metrics, changelog in the form of a graph…
See the project website: http://loki.re for documentation, download, papers and more!