• Software as a service (SaaS)
• Infrastructure as a service (IaaS)
• Platform as a service (PaaS)
• Desktop as a service (DaaS)

So every software vendor that sells their software with a web interface suddenly becomes a Cloud operator, and taps in to the Cloud marketing buzz. Other companies are more careful and think about what they call a cloud and what the don’t call a cloud. IBM for example a has a policy where every initiative that wants to use ‘Cloud’ as a marketing sentence has to comply to the following principles:

• A form of self service
• Some element of virtualization and scalability
• Worldwide availability
• A Pay-as-you-use policy

Also the Open Cloud Manifesto establishes a core set of principles to ensure that organizations will have freedom of choice, flexibility, and openness as they take advantage of cloud computing. While cloud computing has the potential to have a positive impact on organizations, there is also potential for lock-in and lost flexibility if appropriate open standards are not identified and adopted.