Once you have finished the Azure application development process, you need to publish your apps in the Windows Azure Marketplace. At that point you will (hopefully) gain subscribers, and you will need to manage the subscription lifecycle.
An online lab from Microsoft takes you through the process of learning how to publish your Azure applications, services, building block components and premium datasets on the Azure Marketplace. It then teaches the developer how to associate user accounts to an application, how to use Windows Azure AppFabric Access Control Services and how an application should be updated to facilitate the management of the app subscription lifecycle.
