Amazon is hosting so interesting virtualization services called EC2 (Elastic Cloud 2) and S3 (Simple Storage Service).
EC2 is a hardware virtualization service - you basically create a virtual machine and run your software on top of it. You can create as many instances as you want and you only pay for what you use.
S3 gives you a storage API - here too you pay for the space you occupy.
There are some very interesting things which are being deployed on EC2/S3 for example:
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