Microsoft accused of sharing data of Office 365 subscribers with Facebook (theregister.com)

If this is true, there really isn't any true reason why a user would expect it. It's kind-of out of the blue that Microsoft and Facebook would have any connection. Microsoft's services are more or less compulsory work services, and Facebook is in a completely separate leisure space.

In short the only entities that benefits from this is Microsoft who gets more revenue, and Facebook, who gets more user data.

The users are simply being literally sold.