And finally the fourth center of gravity encompasses most all of the other providers, Bittman says. Large vendors, such as IBM, HP, Intel, Microsoft and others, each have their own set of cloud offerings, ranging from Microsoft's Windows Azure platform as a service (PaaS) model, to IBM's SmartCloud, which includes both IaaS and PaaS products. Some of these players, including a growing number of telecommunications carriers such as Verizon, CenturyLink and AT&T, offer a variety of both public and private cloud services, and are making it easier to create hybrid clouds.
AT&T, for example, this month released its Synaptic Compute as a Service, which makes the company's IaaS public cloud compatible with VMware's vCloud Datacenter offering. Recognizing the integration challenge ahead, many vendors are acquiring assets to help ease the transition. Last year, for example, after purchasing IaaS provider Terremark, Verizon bought cloud integration specialty firm CloudSwitch, and IBM bought Cast Iron, another integration company.
So which camp should you bet on if you see a hybrid cloud in your future?
"It's really about answering the question: 'what problem are you trying to solve?'" says Toby Owen, senior manager of hybrid cloud solutions for Rackspace. If it's to transfer and store data, for example, then questions about bandwidth and data transferring could be top of mind. On the other hand, if an enterprise is using the cloud to support bursting, or a sudden spike in web traffic, perhaps price is a more important consideration.
Whatever sways the decision today, it is important to consider that needs may change in the future. Which is why, Bittman says, it is so important to consider interoperability issues going in.