In the category, the cloud service provider offers the capability to build and deploy consumer-created applications using the provider’s cloud infrastructure.

Platform as a Service (PaaS)

Explanation:

In cloud computing, PaaS called platform as a service refers to the provision of a computing platform for developers to create their own custom application. Other two categories of cloud computing are IaaS (Infrastructure as a service) and SaaS (Software as a Service). In the PaaS the servers, cloud storage and network  are automatically handled by the platform only the software and application code are to be managed.

i believe the two important functions that skype uses are nat traversal and user location.good luck        

explanation: