Since I have been mostly writing about the benefits of cloud computing, I would now like to bring up for discussion the market and providers of these services, especially from the point of view of enterprises.
Most enterprises are still trying to understand what cloud computing is and how it could fit their IT processes. The same advantages that I have previously pointed out, still apply in their case, especially the ones related to scalability, when the resources that they need vary, and thus, they have the ability to buy temporary storage, for example. Also, it would allow them to make the conversion from capital expenses to operational expenses. As said here: This is certainly not IT for IT's sake; it is IT for the company's sake.
Recently, I noticed that cloud providers (IaaS, SaaS or PaaS) have been drawing more attention and interest from larger companies, who are trying to enter the cloud computing market. For example, NaviSite was acquired by Time Warner; Terramark was bought by Verizon, and recently, Savvis receiving a 2.5 billion bid from CenturyLink.
Some enterprises might be conformable with using the services offered by Google or Amazon, but they might need specialized services as well, or might want to maintain the ownership of their information. In these conditions, who will be the dominant enterprise cloud providers?
First of all, there are the obvious big players such as Amazon, Rackspace, IBM, AT&T, CISCO, or HP. Furthermore, here is a list of cloud computing providers and consulting companies, most of which are PaaS or IaaS: https://www.cloudtweaks.com/2010/02/list-of-cloud-platforms-providers-and-enablers-2010/. Another list can be found here: https://cloud-computing.findthebest.com/
A virtual machine simulates a computer environment, which can be cloned with just one click, on a single hardware platform. It is something similar to what I did here, where I have personally worked with NaviSite and CISCO. A list of virtualizations platforms can be found here: https://en.wikipedia.org/wiki/Comparison_of_platform_virtual_machines.
In terms of costs, service providers are paid by utility. Some of the elements included in the cost are: memory, CPU, bandwidth, data transfer, etc. To make the whole process transparent and to let companies what costs to expect, Amazon provides a calculator for costs: https://calculator.s3.amazonaws.com/calc5.html
In terms of the software that will be mostly used by the cloud providers, I believe that the market will be dominated by a few large players, not unlike what we see with the three large OS's today, Microsoft, Apple and Linux.
All in all, I believe that the market of enterprise cloud providers will be much diversified. Companies will tend to specialize on providing specific services for cloud computing. No one can truly estimate at the moment how things will evolve and what the main providers will be.
Photo source: https://www.sxc.hu/photo/1000052.