Carl and Richard talk to David Neilsen about doing cloud development. David digs into the various flavors of cloud, defining the differences between Platform-as-a-Service, Infrastructure-as-a-Service and Software-as-a-Service. David is one of the original organizers of CloudCamp, free one day events to help people get started with the cloud. The conversation then digs into the challenge of migrating existing .NET applications to Azure. David finishes by defining the core criteria of cloud computing: On-Demand, Self-Service, Scalable, Measurable. The acronym is OSSM, pronounced 'awesome.'