Software as a Service (SaaS)
SaaS describes using software applications over the internet. SaaS applications run within Internet browsers such as Internet Explorer, Chrome, Safari or Opera and are compatible with any internet connected device. The great advantage of this is that the user can access and use their data on any device regardless of the make, model and operating system it uses.
Platform as a Service (PaaS)
PaaS describes a platform and environment that allow users to build applications and services over the internet. PaaS services are hosted in the cloud and accessed by users simply via their web browser. PaaS is aimed at developers and designers who want to create new software applications using a set of tools offered by the service provider.
Infrastructure as a Service. (IaaS)
IaaS allows the end user to use computer hardware resources such as server space, network connections, and IP addresses from a pool of hardware resource offered by the provider. These resources are drawn from a multitude of servers and networks distributed across numerous data centres owned by the Cloud provider. The user is given access to the virtualised components they require to build their own IT platform.