SaaS stands for Software as a Service, which is a cloud service model that provides the customer with a complete software application that is hosted and managed by the provider. The customer can access the software over the internet, without requiring any installation, configuration, or maintenance on their side. The customer only pays for the software usage, usually on a subscription or pay-per-use basis. A CRM service is an example of a SaaS application, as it allows the customer to manage contacts, organize communication, and track sales activities, without having to worry about the underlying infrastructure, platform, or software development. A public cloud provider is a provider that offers cloud services to the general public over the internet, such as Microsoft Azure, Amazon Web Services, or Google Cloud.

SaaS is different from other cloud service models, such as IaaS, DBaaS, or PaaS. IaaS stands for Infrastructure as a Service, which provides the customer with the basic computing resources, such as servers, storage, network, and virtualization. The customer is responsible for the operating system, middleware, runtime, application, and data. DBaaS stands for Database as a Service, which provides the customer with a database management system that is hosted and managed by the provider. The customer is responsible for the data and the queries. PaaS stands for Platform as a Service, which provides the customer with a platform to develop, run, and manage applications without worrying about the infrastructure. The customer is responsible for the application code, data, and configuration. References: Cloud Service Models - CompTIA Cloud Essentials+ (CLO-002) Cert Guide, What is SaaS? Software as a service explained | InfoWorld, What is SaaS? Software as a Service Explained - Salesforce.com, [What is SaaS? Software as a Service Definition - AWS]