[](/sswow) Just pulling your leg, man.
If we used Github, it could be drafted in Markdown, which we'd all be familiar with, and easily rendered for preview. On the other hoof, I don't think anyone else has Github accounts. Do you? They can be made anonymous.
Alternatively, perhaps a collaborative web editor, like firepad?
free visual studio online (up to 5 people). It's well integrated into visual studio and you can decide between svn and git systems. If you actually need to see each other writing at the same time: Well, why would you want to do that? It's possible, but I won't recommend it. Try google docs/drive, word online or some of these other coding pads like http://www.firepad.io/
He encontrado un editor de texto colaborativo de código abierto, aunque parece no incorporar por defecto soporte de comentarios. No lo he mirado a fondo ya que me estoy centrando en lo de Android, pero lo dejo para que le echéis un vistazo: http://www.firepad.io