Suggestion: the CommonMark website could be put into a Git repository. The site’s text, along with any documentation and the spec, could be written in Markdown (of course) and converted to HTML via a static site generator such as Jekyll or Middleman. The community could then contribute the documentation via pull requests on GitHub.
What do you mean ? The only significant place to contribute is spec, it’s already in root of stmd git repo on github.
Perhaps there is no present need then.