Consumers gain access to applications via third-party providers. These applications are managed “in the cloud”, freeing consumers from necessary software maintenance.

Platform as a Service: (PaaS):                    

Consumers gain access, via third-party providers, to applications created using programming languages and tools.

Infrastructure as a Service (IaaS):            

Consumers are provisioned with access to processing, storage, networks, and other computing resources on which the consumer is able to deploy and run software. The consumer doesn’t manage or control the infrastructure, as these are located offsite ('in the Cloud'), but does control operating systems, storage, applications and possibly certain networking components (e.g. host firewalls).

Consumers may choose to employ one or several of these Online Services (or Cloud Computing) models depending on their current needs and future IT strategy.