The boundaries between these layers have become increasingly fluid, with most of today’s cloud companies at least attempting to straddle two of them.
Today, Amazon is a dominant provider of public cloud infrastructure, through offerings such as the Simple Storage Service (S3) and Elastic Compute Cloud (EC2). Amazon continues to innovate, and to drive the price of basic infrastructure down, but it’s far from alone. Companies like Rackspace and CloudSigma compete in providing similar cloud infrastructure. Further up the cloud stack, platforms from Heroku, Engineyard and Apprenda are among those delivering tools that developers need in order to deliver compelling experiences to their own customers. And in the area of Software as a Service (SaaS), Salesforce continues to blaze its own bright trail. Google, Microsoft and others are transforming the office productivity market by delivering free or cheap cloud-based collaboration tools.