Google Docs
A powerful document creation platform. Supports features such as: realtime collaboration, offline document editing, inline document comments, search and full differential changelog. Free for personal use, costs for commercial
documentation free commercial
Hackpad
A lightweight, markdown based, document creation platform packed full of features such as: realtime collaboration, offline document reading (via dropbox), in documment comments, search / tagging and full diff'd changelog. Private workspaces free for the first 5 users, Public workspaces always free.
documentation free commercial
r10k
r10k provides a general purpose toolset for deploying Puppet environments and modules. It implements the Puppetfile format and provides a native implementation of Puppet dynamic environments.
linux windows osx open-source free scm
RocketGit
Free (as in speech and as in beer) software (AGPLv3+) for hosting Git® projects, both public and private.
linux free scm vcs