Google docs is my favorite collaborative authoring tool for the classroom. Over the years they have enriched the product with a number of enhancements that are valuable in the classroom.
Peer Review and Commenting
Peer editing and review are simplified with Google Docs. Students can share documents with each other or their teacher. Teachers gain the ability to review student writing in real-time. They can add comments or notes where appropriate to guide student progress. Long gone are the days of collecting a rough draft - conducting an autopsy on it and then waiting for the final copy. Now you can intervene immediately as well as review how students construct their writing by reviewing the history.
When reviewing a written work you can insert comments which will appear on the right side of the screen. Just highlight the text that you want to add a comment near and click INSERT - COMMENT. The comment feature allows for discussion which can represent a small conference between the reviewer and the author about their work.
Another great feature is the RESEARCH TOOL. When activated the author can search for text, images, maps or any other relevant content without leaving the document. Click on TOOLS - RESEARCH to utilize this feature.
Auto Save, Revision History, and Spelling/Grammar checks are long-time features that are useful for students and teachers. Collaborative projects are simplified by reviewing revision history to get a snapshot of who the contributors to a document are.