Cloud computing is a fundamental change in the use of ICT. Instead of using hardware and software you own and manage, now you buy ICT services from other suppliers via the Internet. If you need additional capacity you can easily scale up with the cloud infrastructure and many network connections.
Until now, you had to invest up-front in hardware and software before consuming ICT. The consumption model of cloud computing is characterized by operational expenditures. You pay for a flexible subscription for the flexible functionality or capacity, that you know that you definitely need, i.e. 'pay as you go'.
Cloud Providers like Amazon, Google and Salesforce.com have paved the way for the cloud as a distribution channel and consumption model. There is a trend emerging for suppliers to offer new features and functionality exclusively in the cloud.