StepShot - Make knowledge sharing more time-efficient!
Documize - Enterprise-grade wiki and knowledge management platform
HelpSmith - HelpSmith is a help authoring tool to create CHM HTML help files, manuals, and PDF documents.
Boardist - Personal workspace for all the data
FastHelp - FastHelp is a Windows Help File Generator that produces online and offline documentation.
ReadTheDocs - Spend your time on writing high quality documentation, not on the tools to make your documentation work.