Breaking cloud computing into categories makes it easier to understand how you can use it in your business and less confusing.
Application-as-a-service (software-as-a-service): This is any application that is delivered over the platform of the Web to a user, typically accessing the application through a browser. Examples include Salesforce.com, Google Docs, Gmail, and Basecamp.
Storage-as-a-service: This is the ability to use storage that physically exists at a remote site but is logically a local storage resource to any application that requires storage. Apple’s iDisk is a example.
Integration-as-a-service: This is the ability to deliver a complete integration stack from the cloud, including interfacing with applications, semantic mediation, flow control, and integration design. Example Boomi.com. We used it recently to integrate Salesforce.com and Microsoft Dynamics GP.
Database-as-a-service: This provides the ability to use the services of a remotely hosted database, sharing it with other users, and having it logically function as if the database were local.
Information-as-a-service: This refers to the ability to consume any type of information, remotely hosted, through a well-defined interface such as an API. Examples include stock price information, address validation, and credit reporting.
Process-as-a-service: This refers to a remote resource that can bind many resources together, such as services and data, whether hosted within the same cloud computing resource or remotely available, to create business processes.
Platform-as-a-service: This is a complete platform — including application development, interface development, database development, storage, and testing — delivered through a remotely hosted platform to subscribers. Platform-as-service providers provide the ability to create enterprise-class applications for use locally or on-demand for a small subscription price. Example: Force.com
Infrastructure-as-a-service: This is the ability to remotely access computing resources . In essence, you lease a physical server that’s yours to do with as you will, and for all practical purposes it is your datacenter. You get access to the entire machine and the software on that machine.
Security-as-a-service: This is the ability to deliver core security services remotely over the Internet . While the typical security services provided are rudimentary, more sophisticated services are becoming available such as identity management.
Management/governance-as-a-service: This is any on-demand service that provides the ability to manage one or more cloud services. These are typically simple things such topology, resource utilization, virtualization, and uptime management.
Testing-as-a-service: This is the ability to test local or cloud-delivered systems using testing software and services that are remotely hosted . It should be noted that while a cloud service requires testing unto itself, testing-as-a-service systems can test other cloud applications, Web sites, and internal enterprise systems, and they do not require a hardware or software footprint within the enterprise .