Co-authoring. Multiple people to view and edit documents simultaneously
Versioning. Version control to track and manage changes
Site mailbox. Single location for email and documents. Shared inbox in Exchange online that members of SharePoint Online site can access
Sharing. Share documents with customers
Apps. Apps are a great way to add more functionality to SharePoint. For example you could embed Yammer feeds on your SharePoint sites and invite customers to social community discussions
Delve.Easy to find and discover useful and relevant content
External sharing. Easily share content with people outside your organization who do not have licenses for your Organization’s Microsoft Office 365 subscription.
Social collaboration with Yammer. Find experts and build relationships, grow your network by following people, stay up-to-date by following documents and interact with others
E-discovery.Help, identify and deliver electronic information that can be used as evidence on demand
Records management. Secure and protect artefacts as records across the organization
Auditing. Rich auditing reports across the site and document lifecycle