Big O is really showing up & so is cloud computing:
Software-as-a-Service (SaaS) is the delivery of applications-as-a-service, probably the version of cloud computing that most people are used to on a day-to-day basis. The underlying hardware and operating system is irrelevant to the end user, who will access the service via a web browser or app; it is often bought on a per-seat or per-user basis.
According to researchers IDC SaaS is -- and will remain -- the dominant cloud computing model in the medium term, accounting for two-thirds of all public cloud spending in 2017, which will only drop slightly to just under 60% in 2021. SaaS spending is made up of applications and system infrastructure software, and IDC said that spending will be dominated by applications purchases, which will make up more than half of all public cloud spending through 2019. Customer relationship management (CRM) applications and enterprise resource management (ERM) applications will account for more than 60% of all cloud applications spending through to 2021. The variety of applications delivered via SaaS is huge, from CRM such as Salesforce through to Microsoft's Office 365