Web hosting is a service that enables customers to deploy a website quickly. This is an example of:

IaaS (Infrastructure as a Service) would require the customer to manage virtual machines, operating systems, and network components, which is more granular than simply deploying a website quickly onto a pre-configured environment.

SaaS (Software as a Service) provides complete, ready-to-use software applications, whereas web hosting involves deploying the customer's custom application code onto a platform.

Platform as a Service (PaaS) provides a platform environment for customers to develop, run, and manage applications without the complexity of building and maintaining the infrastructure. Web hosting services often fall under PaaS because the provider manages the underlying servers, operating systems, and web server software, while the customer deploys and manages their application code.

On-demand software describes a characteristic of cloud services but is not a specific cloud service model like IaaS, PaaS, or SaaS.