The beauty of the cloud is that the level and amount of service one can obtain varies greatly. For something as simple as a basic hosting plan to run your web application, you can use any number of services that are considered a Platform as a Service (PaaS). This is a service that provides a platform for you to host and run your web application. Increasing in scale and complexity, you can turn to an Infrastructure as a Service (IaaS) provider, which offers an entire cloud-based data center at your disposal.
You can learn more about the differences between IaaS, PaaS, and Software as a Service (SaaS) by reading a detailed article available at http://www.rackspace.com/knowledge_center/whitepaper/understanding-the-cloud-computing-stack-saas-paas-iaas ...
