The hot new cloud buzzword for 2012 is "cloud burst."
A "cloud burst" in this case is a quick in-and-out use of cloud resources to do some job that can't be done as effectively any other way. An example is Renderman on Demand, a system for quickly rendering complex screen images using Pixar's Renderman, a cloudbursting technology called GreenButton, and the Microsoft (MSFT) Azure cloud.
Cloud bursting gives big organizations an incentive to use the cloud. This provides a big financial lift for all owners of public clouds - not just Microsoft, but Google (GOOG), Rackspace (RAX) and Amazon (AMZN) as well.
This is a buzzword that may only now be coming into prominence, but the public cloud companies have been talking about it since 2008. Cloud bursting is integral to the public cloud's business case, as it's the quick, intermittent use of resources that makes the public cloud business case so interesting.
Over the long term, of course, this benefits all cloud vendors. A customer may use the idea as justification for investing in a private cloud. But the capability is available right now, practically on-demand, on public clouds, and will remain most efficiently used in those public clouds than in private clouds for some time to come.
All this depends, in part, on moving data back-and-forth quickly between a local system and the cloud. Solutions to that problem are here. They depend on being able to replicate, on the cloud, a data volume that may occupy a customer's entire Wide Area Network (WAN). Those solutions are here. Cloud bursting through gateways is getting easy.
In the longer run, cloud bursting will also help IT organizations justify the construction of private clouds, but solutions for that are some time away, despite enterprise vendors' rush to claim them.