This document discusses Microsoft Azure's platform as a service (PaaS) offerings for hosting line of business applications, application infrastructure, and developer environments. It outlines Azure's capabilities for provisioning base operating system images, writable disks, and connectivity options including data synchronization, messaging, and both IP-level and site-to-site virtual private networking. The document also provides guidance on when a virtual network would be needed, such as for persistent IP addresses, hybrid cloud applications, or deploying Active Directory in Azure.