Most of the buzz around the cloud has centered on infrastructure as a service (IaaS). However, IaaS is no longer good enough. Sure, you can forgo buying servers and run everything virtually on Amazon's EC2 server farm. So what? You still have to manage it, and to do that you'll have a growing IT bureaucracy. Companies that want to focus on writing their code and not have to think about application servers at all are now looking to platform as a service (PaaS).