Cloud hosting

Cloud hosting is a technology where website hosted on a cloud hosting operates on a clustered servers where online operations are not limited to a single server. By handling security, load balance and hardware resources virtually, the website has access to the processing power of a number of servers that are distributed in real time.
Cloud hosting benefits the users from various angles. It's scalability and cost efficient is the commonly known advantages.

AWS - Amazon Web Services
Since early 2006, Amazon Web Services (AWS) has provided companies of all sizes with an infrastructure web services platform in the cloud. With AWS you can requisition compute power, storage, and other services-gaining access to a suite of elastic IT infrastructure services as your business demands them.
With AWS you have the flexibility to choose whichever development platform or programming model makes the most sense for the problems you're trying to solve. You pay only for what you use, with no up-front expenses or long-term commitments, making AWS the most cost-effective way to deliver your application to your customers and clients.
Using Amazon Web Services, an e-commerce web site can weather unforeseen demand with ease; a pharmaceutical company can "rent" computing power to execute large-scale simulations; a media company can serve unlimited videos, music, and more; and an enterprise can deploy bandwidth-consuming services and training to its mobile workforce.

Google App Engine
Google App Engine lets you run your web applications on Google's infrastructure. App Engine applications are easy to build, easy to maintain, and easy to scale as your traffic and data storage needs grow. With App Engine, there are no servers to maintain: You just upload your application, and it's ready to serve your users.
You can serve your app from your own domain name (such as http://www.example.com/) using Google Apps. Or, you can serve your app using a free name on the appspot.com domain. You can share your application with the world, or limit access to members of your organization.
With App Engine, you only pay for what you use. There are no set-up costs and no recurring fees. The resources your application uses, such as storage and bandwidth, are measured by the gigabyte, and billed at competitive rates. You control the maximum amounts of resources your app can consume, so it always stays within your budget.
App Engine costs nothing to get started. All applications can use up to 500 MB of storage and enough CPU and bandwidth to support an efficient app serving around 5 million page views a month, absolutely free. When you enable billing for your application, your free limits are raised, and you only pay for resources you use above the free levels.