The new co-authoring functionality in Microsoft Office 2010 makes it possible for multiple users to work productively on the same document without intruding on one another’s work or locking each other out.
You can use this new co-authoring functionality in Microsoft PowerPoint 2010 and Microsoft Word 2010 documents on SharePoint Server 2010. New co-authoring functionality is also supported in Excel Web App and OneNote Web App.
When two or more people are working on a document at the same time, they might make changes that conflict with each other. Conflicts can occur when one person works offline and then saves the document to the server. Conflicts can also occur when two people work on the same part of a document at exactly the same time.
When edits conflict, Word displays a notification the next time that you save the document. The conflicts must be resolved before you can save the document to the server.
Note: All changes in the document are saved on your computer even when the document contains conflicts. But the changes aren't saved to the server until the conflicts are resolved.
When conflicts exist, Word notifies you by displaying the following:
A message bar
A notification in the status bar
A notification in Backstage View
You can click any of these entry points to work in Conflict Resolution Mode and resolve all conflicting changes. In Conflict Resolution Mode, a Resolution pane lists the conflicts, and the Conflict tab appears on the Ribbon.
When you click a conflicting change in the pane, the conflicting portion of the document is highlighted. The conflicting changes that you made are marked up in pink.
On the Conflict tab, click Accept to keep your change, or click Reject to remove your change.