Hardware as a Service (HaaS) is a type of cloud computing service that provides physical hardware resources, such as servers, storage, and networking, on a pay-as-you-go basis. It is not a characteristic of IaaS, which typically refers to the delivery of virtualized computing resources over the internet.

IaaS offers reduced costs by allowing businesses to pay only for the resources they use, eliminating the need to purchase and maintain their own hardware and software infrastructure.

Virtualization is a fundamental technology used in IaaS to create multiple virtual machines (VMs) on a single physical server. This allows for efficient resource utilization and isolation of applications.

Elasticity refers to the ability of IaaS to scale resources up or down dynamically based on changing requirements. This allows businesses to respond quickly to fluctuations in demand without having to provision additional hardware.

Managed Cloud is not a type of IaaS service model. It refers to a cloud computing service where the cloud provider manages the infrastructure, including hardware, software, and applications, on behalf of the customer.

Multi-tenancy is a key characteristic of IaaS that allows multiple customers to share the same physical infrastructure while maintaining isolation and security of their respective resources.

Developing and maintaining applications is not a responsibility of the IaaS provider. IaaS providers typically focus on providing the infrastructure and resources necessary for customers to run their own applications.

Self-service provisioning is a key feature of IaaS that allows customers to provision and manage resources on demand through a self-service portal or API, without the need for manual intervention from the cloud provider.

Vendor lock-in is not a benefit of using IaaS. In fact, one of the key advantages of IaaS is the ability to choose from multiple cloud providers and avoid vendor lock-in.

Global reach refers to the ability of IaaS providers to offer their services in multiple geographic regions around the world, allowing customers to deploy their applications and data in locations that best suit their needs.

Managing customer relationship management (CRM) systems is typically not a common use case for IaaS. CRM systems are often deployed on-premises or through software-as-a-service (SaaS) offerings.

Service level agreements (SLAs) are contracts between cloud providers and customers that define the performance and availability levels of the IaaS services. SLAs ensure that customers receive consistent and reliable service.

Brand recognition is not a key consideration when choosing an IaaS provider. Instead, factors such as cost, security, reliability, and the provider's track record and expertise in delivering IaaS services are more important.

Isolation is a key characteristic of IaaS that ensures that resources allocated to one customer are isolated from those of other customers, providing security and data protection.

Community Cloud is not a type of IaaS deployment model. It refers to a cloud computing model where resources are shared among a specific group of organizations or communities with common interests or goals.