Platform-as-a-Service (PaaS) is not a fading fad.  PaaS is an important middle part of the cloud software stack that has truly helped drive the mass adoption of cloud computing as a viable delivery method for software applications.

Platform offers simple tools to create, control and manage computing infrastructure.  The infrastructure itself isn’t too different then traditional hardware and software such as CPU, graphic cards, memory, storage and operating systems.  All this equipment is expensive to purchase and costly to maintain so PaaS is basically a management utility for IaaS.  PaaS is also a software development utility that allows developers with little, or no, actual coding ability to create feature-rich end-user applications.  Salesforce is a shining example of a wildly popular Platform-as-a-Service.