Microsoft’s definition

Cloud computing is the delivery of computing services, including servers, storage, databases, networking, software, analytics, and intelligence, over the internet (“the cloud”) to offer faster innovation, flexible resources, and economies of scale. You typically pay only for cloud services you use, helping you lower your operating costs, run your infrastructure more efficiently, and scale as your business needs change. Defining Cloud Computing

• from Microsoft's What Is Cloud Computing?

Delivery

Delivery of computing services

• Servers, storage, databases, etc.
• Over the internet ("the cloud")
• On demand

Advantages

Do things better and faster

• Server in an instant
• Scale up and down
• Greater flexibility

Cost efficiency

Pay only for what you need

• Lower operating costs
• Greater efficiency
• Scale as business needs change

Summing it up

The Cloud is:

• Multiple vendors
• Multiple servers and data centers
• On-demand delivery of compute services over the internet
• Do things better and faster, with greater flexibility
• Pay only for what you need