The document discusses different cloud computing models including Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS). It provides examples of popular cloud platforms for each model such as Google Apps for SaaS, Force.com and Google App Engine for PaaS, and Amazon EC2 for IaaS. It also compares the development process for traditional on-premise systems versus PaaS and IaaS hosted environments.