Co-authoring in SharePoint 2013 – things you should now

The co-authoring feature in SharePoint allows multiple users to work on a specific document simultaneously. This is enabled by a client-server technology which was first introduced in Office 2010 and SharePoint 2010 called Cobalt which allowed parts of an Office documents to be synchronized back to SharePoint. This technology was initially created to optimize network traffic from the clients to Office since Office would only send updates or the compressed differentiation (or delta) of the file back when saving a file.  

   Co-authoring is not supported on all of the Office documents in all of the different clients and it also seems that there is not a lot of change between 2010 and 2013. Things which might not seem so obvious:

• There also does not seem any difference in co-authoring experience when you compare SharePoint 2013 with Office Web Apps and SharePoint 2010 with Office Web Apps.
• For both SharePoint 2010 and SharePoint 2013 – no co-authoring available from Office clients (not in Excel 2010 nor in Excel 2013)
• Co-authoring is available using the Excel Web Apps – both in SharePoint 2010 and SharePoint 2013
• Co-authoring requires that the check-in/check out functionality is not enabled on SharePoint document libraries
• Co-authoring will work in most browsers (Internet Explorer, Firefox, Safari and Chrome) and on most platforms.
• Theoretically there is no limit on the number of users who can co-author a document.
• Office 2010 users have the same set of co-authoring features when they open documents from SharePoint 2013 or SharePoint Online as they do when they open documents from a SharePoint 2010 document library. 

References:

• Overview of co-authoring in SharePoint 2013
• Document collaboration and co-authoring  - more end user focused documentation