With the Azure Stack, you can deploy your applications on your on-premises (private) cloud, just like you would do in Azure - you're essentially retargeting the app. Our ultimate goal is to empower maximum application agility.
To enable the same deployment experience, Microsoft is bringing the same Azure portal, user experience framework, and underlying IaaS/PaaS APIs and services to your on-premises environments. We're also being thoughtful in which services we bring on-premises so that enterprise customers get maximum value.
We want to enable our customers and partners to run Azure in their datacenter in a way that's appropriate to their business requirements. We understand that not everybody operates at the hyper-scale that Microsoft does - as such, we will translate Microsoft's cloud designs and bring them to customers so it's easy to consume while enhancing flexibility and security in datacenter operations.