I've contributed to many sources of online documentation, but I've also built up about 300 pages of useful notes. I want to share more. I don't want to create yet another site and needlessly fracture documentation sources, so there are a lot of existing sites and sources I am going to be offloading to (emacs wiki comes to mind).
But I also have a vision of a site for material which doesn't fit well in existing sources, about any free software, and has some opinionatedness / style that official documentation does not generally afford. One very common and annoying practice of people who do good writing on technical topics is to use a blog or site which doesn't invite collaboration and improvement by others. So... I've started ofswiki.org (update Aug 2019, Ive retired it. blog post forthcoming).
It's really easy to setup a basic Mediawiki instance. Of course, I had to geek out on it. That process became the first page.