Introduction to Amazon Elastic Compute Cloud

Amazon EC2 is a web service that enables you to allows you to provision on-demand compute capacity from Amazon's world class data centers.

This means you can allocate or release resources within minutes, not hours or weeks, as your application requires. Most importantly, you only pay for what you use. If you use a server instance for an hour, you pay for an hour. If you use an instance for a year, you pay for a year.

Although the applications for Amazon EC2 are only limited by your ingenuity, there are popular ways in which our customers use Amazon EC2:

Scalable Applications—you can build a scalable application that shrinks or expands to meet your current demands. This can help you use only the compute resources that you need and can help you respond to events where a mention on a popular news site can result in a dramatic spike in traffic.
Temporary Events—you can use Amazon EC2 for temporary solutions and one-off events that would require you to maintain a fleet of compute resources that are normally idle. This includes hosting conferences in virtual worlds, live blogging, distribution of newly released media, and short-term promotional websites.
Batch Processing—you can use Amazon EC2 for projects that require massive compute resources which would be expensive to build on your own. This includes video and image processing, financial data processing, and science and research applications.