- Editing a document and reviewing the revision history
- Using the built in chat window
- Leaving comments/starting discussions about specific text
- Leaving comments/starting discussions about the entire document
- Configuring your comment notification settings
- The new Can Comment sharing permission recently added to Google Docs
Note: These collaboration tools are always being enhanced by Google and may look/act differently in the future.
I recommend watching the clip in full screen mode. http://youtu.be/iv8-yQJVl6k