"Cloud computing is ... the user-friendly version of grid computing."
- Trevor Doerksen

"Most computer savvy folks actually have a pretty good idea of what the term "cloud computing" means: outsourced, pay-as-you-go, on-demand, somewhere in the Internet, etc."
- Thorsten von Eicken

"In order to discuss some of the issues surrounding The Cloud concept, I think it is important to place it in historical context. Looking at the Cloud's forerunners, and the problems they encountered, gives us the reference points to guide us through the challenges it needs to overcome before it is adopted."
- Paul Wallis

"I would like to propose a 'Cloud Pyramid' to help differentiate the various Cloud offerings out there. [At the top of the pyramind] users are truly restricted to only what the application is and can do. Some of the notable companies here are the public email providers (Gmail, Hotmail, Quicken Online, etc.). Almost any Software as a Service (SaaS) provider can be lumped into this group.

As you move further down the pyramid, you gain increased flexibility and control but your a still fairly restricted to what you can and cannot do. Within this Category things get more complicated to achieve. Products and companies like Google App Engine, Heroku, Mosso, Engine Yard, Joyent or force.com (SalesForce platform) fall into this segment.

At the bottom of the pyramid are the infrastructure providers like Amazon’s EC2, GoGrid, RightScale and Linode. Companies providing infrastructure enable Cloud Platforms and Cloud Applications. Most companies within this segment operate their own infrastructure, allowing them to provide more features, services and control than others within the pyramid."
- Michael Sheehan

"The web fanatics and blogosphere would have you believe that all applications will move to the web. Some will, most will not. Reliability, scalability, security, and a host of other issues will prevent most businesses from moving their mission critical applications to hosted services or cloud based services. The risk of failure is too great.

Amazon is the leader in cloud based services, but even Amazon has experienced down times for its own business. Cloud services will continue to improve. But my guess is the uptake will take longer than most people predict."
- Don Dodge

"Today's combination of high-speed networks, sophisticated PC graphics processors, and fast, inexpensive servers and disk storage has tilted engineers toward housing more computing in data centers. In the earlier part of this decade, researchers espoused a similar, centralized approach called "grid computing." But cloud computing projects are more powerful and crash-proof than grid systems developed even in recent years."
- Aaron Ricadela

"When virtualizing applications to be used by people who care nothing about computers or technology - as is mostly the case with Clouds - the key thing we want to virtualize or hide from the user is complexity. Most people want to deal with an application or a service, not software. ... The more intelligent we want [computers and computer applications] to be - that is, intuitive, exhibiting common sense and not making us have to constantly take care of them - the more smart software it will take. But with cloud computing, our expectation is that all that software will be virtualized or hidden from us and taken care of by systems and/or professionals that are somewhere else - out there in The Cloud."
- Irving Wladawsky Berger


"I view cloud computing as a broad array of web-based services aimed at allowing users to obtain a wide range of functional capabilities on a ‘pay-as-you-go’ basis that previously required tremendous hardware/software investments and professional skills to acquire. Cloud computing is the realization of the earlier ideals of utility computing without the technical complexities or complicated deployment worries."
- Ben Kepes


"Cloud computing really comes into focus only when you think about what IT always needs: a way to increase capacity or add capabilities on the fly without investing in new infrastructure, training new personnel, or licensing new software. Cloud computing encompasses any subscription-based or pay-per-use service that, in real time over the Internet, extends IT's existing capabilities."
- Bill Martin