Did you ever had a feeling that you nurture a brilliant business idea which would have been revolutionary success if (and only if) it saw the daylight!But then you thought of so-called necessary overloads of hosting,hardware,software,scalability etc. and then saw your enthusiasm vanish?Well,not so long ago software making looked like this.
The diagram to your right shows a very simplistic representation of a traditional software building workflow.Let us call the group of initial activities like Idea generation,Idea conception,Business Plan creation and Funding as the "Application Conceptualization" phase.And then you proceed towards the Application Implementation phase marked by the ordeal of procuring hardware,software,design and development causing a huge outflow of funds.
You try to subdue the voice of a skeptic deep down your mind which whispers "What if the business does not become as successful as deemed?What about the massive cost of ownership of infrastructure (hardware and software)?" as you transit to the Realization phase.
Or even if your business is just doing mediocre, what about the massive infrastructure that you have bought?Are they just e-waste now?
The third is the voice of eternal optimism "Can your infrastructure survive the massive traffic, if it becomes (we at Surprised believe that it will definitely become) highly popular?How much more you have to pay for infrastructure and software redesign to increase scalability ?"Well,fortunately you don't have to worry about all of the questions above as PaaS (Platform As A Service) comes to your rescue and for the skeptics (yes!with certain limitations and workarounds to address those).The diagram to your left shows the modified workflow.With PaaS in place you don't have to worry and shell millions of dollars in buying neither hardware (think appengine -think Google's infrastructure) nor software (think opensource)!Last but not the least the application built on the PaaS are automatically scalable and de-scalable (appengine) .You pay only for what you use and the perpetual cost of ownership is reduced manifolds consequently increasing the ROI.

So,go ahead and implement your next groundbreaking business on top of the cloud.