"There’s no mention of interoperability with other clouds like Google or Salesforce.com; that will have to be left to third parties like Vordel"
From Cloud Computing Journal: http://cloudcomputing.sys-con.com/node/1003149
Besides security, the other big push-back against Cloud Computing is interoperability. Most organizations do not want to have to choose one Cloud Computing vendor exclusively. Certainly, in cases like the US Government (with its new emphasis on Cloud Computing) , using a provider which doesn't explicitly offer interoperability with other providers is unthinkable.
Gateways act as the pivot point between applications and Cloud-based services, as well as between the services themselves. They provide the link from local applications up to the cloud, the "on-ramp". They also mediate between different Cloud providers.
Unfortunately, when a new Cloud Platform doesn't address the interoperability issue, it is adding to the problem, not fixing it. Gateways are the answer to that particular problem.
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