Application platform as a service or aPaaS is a cloud computing category. Cloud computing is an umbrella term for computer services accessible (and adjustable) over the internet.
Betty Blocks is an application platform as a service. This category includes building, designing, developing and managing (business) web-applications. Distinctive components are speed and flexibility. The platform is model-based and by using the visual model builder, applications are designed rapidly and intuitively, without programming. 8-10x faster than regular programming.