I and a friend have been doing something I think is a little better for a while. We just have the document in github, and use a jekyll task to render it, so yo

I and a friend have been doing something I think is a little better for a while. We just have the document in github, and use a jekyll task to render it, so you can edit it in your markdown compatible ide and sync to github, you can edit it online on github, you can add notes to specific line numbers in commits, you can submit pull requests, get notifications, etc., etc. In fact, I was thinking about writing something a bit like this that used github as a backend, since it's working so well.