Important! When accessing Revision History and 'Restoring a Previous Version', no changes are 'eliminated!' The selected version is simply moved to the top of the revision history panel. This is huge: it means that students can't inadvertently (or intentionally) remove edits that form the history of the collaborative document!
Thanks for posting this resource. I'm just about to get started on some presentations and I wanted my students to use this or Vuvox, because PowerPoint is soooooo done. Thanks.