CRM Online to SharePoint Online Integration using REST and ADFS

Accessing SharePoint Online 2013 REST services with SSO via ADFS (Active Directory Federation Services) from CRM Online provides loads of potential opportunities, especially now that SharePoint offers a huge REST API. You can call REST from a CRM Online Plugin or Custom Workflow activity with no dependencies on SharePoint Client dll's or Azure getting in the way, It is fairly awesome I must say.