With simultaneous editing in Office 365 your employees can save time by working together on the same document and can easily bounce ideas off of each other. In the past, employees would have to email the file and keep updating it as they made changes. Now they can make all the changes on the same document avoiding countless emails back and forth. This synthesizes all the work onto the same document, so there is no longer multiple versions of the same document.
For example, your team can work in Web Apps for a collaborative working meeting to get a shared project done. If someone on your team isn't available that teammate can chose to make revisions whenever he's able to. His changes will sync up to the document stored in the cloud when he saves. Even if he is offline, his changes will sync back up to the cloud when he gets back online. What are you waiting for? Start collaborating now!
All Functionality Requires SharePoint Online as the document management system.
To read more about co-authoring click here for the full article.