Dozuki - Dozuki is a web-based tool for creating and distributing step-by-step documentation.
Documize - Enterprise-grade wiki and knowledge management platform
REWO - REWO is a knowledge documentation and distribution solution, which drastically improves capturing, visualizing and communicating knowledge.
ReadTheDocs - Spend your time on writing high quality documentation, not on the tools to make your documentation work.
StepShot - Make knowledge sharing more time-efficient!
HackMD - Fast and flexible, real-time collaborative markdown, inspired by Hackpad.