The Microsoft Application Platform (MAP) is a technology stack used for the development and deployment of high end enterprise level business applications. It provides for both on-premise, cloud and hybrid based deployments.
Note that SQL Server is used to provide the data layer for all of the key components of MAP including BizTalk, SharePoint, CRM and any custom components.
The above demonstrates the power of MAP. Windows provides the infrastructure. SQL Server provides the data platform. SharePoint provides the portal with authentication and security to manage permissions and BizTalk provides the message handling and workflow capabilities.