If your head hasn't been lost up in the cirrus or cumulus, you've probably heard of cloud computing over the last few years.
"The cloud" has figured prominently in President Barack Obama's technology initiatives, in the business plans of familiar tech giants such as Google, Amazon, and Microsoft, and even in a New Yorker cartoon last month - depicting a parachutist struggling to use a laptop.
It's also been the occasional butt of skeptics, such as Oracle co-founder Larry Ellison.
"It's databases and operating systems and memory and microprocessors and the Internet. And all of a sudden, it's none of that - it's 'the cloud,' " Ellison said - in a speech you can still pull down from the YouTube section of the cloud.
Oracle now offers "Premier Cloud Services," but Ellison had a point. For a decade, Oracle had rented its enterprise-resource-management system to corporate customers who didn't want to invest in their own hardware, software and IT personnel - a key advantage of using the cloud. So had other firms that pioneered "software as a service," one of the buzz phrases of the cloud era.
Still, that doesn't mean cloud computing is a nebulous idea or marketing ploy. Advocates such as Patrick Harr, Hewlett-Packard's vice president of global cloud strategy, argue that recent technological and business developments make "the cloud" a truly different way of using computer resources.
"The cloud is the great equalizer," Harr said in an interview. It offers companies and consumers access to user-friendly services that might otherwise require large expenses for software, hardware, and training. And that access can often be available from anywhere on the Internet.
For businesses, it also offers access to resources that otherwise would be unthinkable.
Harr said DreamWorks Studios uses HP's cloud services for rendering films - the hugely data-intensive process that brings together all of the digital elements of a full-scale animation. Even with powerful computers, rendering a segment of a movie can take days, he said.
"If I'm generating a new movie, I only do this once or twice a year," Harr said. "As a company, I don't want to go out and buy thousands of servers for that." Thanks to HP's cloud services, DreamWorks doesn't have to.
Still confused? Here are answers to some basic questions:
WHAT IS CLOUD COMPUTING? Ellison isn't wrong: It's databases, operating systems, memory, microprocessors, and the Internet, all rolled into a package. But with the cloud, the whole really is greater than the sum of the parts.
Harr said two key advances distinguish cloud computing from earlier versions of remote hardware and software rental and mark "a fundamental technological shift."
One is "multi-tenancy," in which many businesses can take simultaneous advantage of a huge pool of powerful resources such as HP's tens of thousands of servers. A small business might just require a tiny portion of resources - perhaps just a section of a single server that hosts a dozen "virtual machines," each emulating a stand-alone computer. A large business might use hundreds of servers.
The other key is automation of crucial tasks, such as responding to a sudden need for extra resources. With in-house technology, a retailer might be overwhelmed by a holiday surge in demand, or a media company by a video that goes viral and generates millions of hits. With the cloud, extra resources can be deployed rapidly and seamlessly.
WHO OFFERS CLOUD SERVICES? The list is long and growing. It's headed by giants such as Google, HP, and Amazon, but includes niche providers as well - sometimes via partnerships between software and hardware companies.
Microsoft CEO Steve Ballmer was in Malvern, Pa., last week to launch a new Microsoft Technology Center, a 17,500-square-foot facility that includes a server farm and is part of the software giant's cloud-centric strategy.
"When you use a cloud-based service, there's nothing you have to install or deploy," said Karen Del Vescovo, Microsoft's district general manager. "This provides you access to the information and the backup from anywhere."
Microsoft says 70 percent of its software developers are working on cloud-related products and services - a figure that will rise to 90 percent within a year.
WHO USES THE CLOUD? Consumers who use Gmail or other Web-based mail services are essentially cloud users. So are interactive gamers or people who use photo services like SnapFish or Flickr, which provide anywhere, any-time access to your digital pictures, even at Grandma's.
For now, old habits and computers still bundled with e-mail and document software may keep consumers using traditional programs. But small businesses increasingly see value in the cloud as a way to control information-technology expenses - and headaches.
Swedesboro, N.J.-based L&L Kiln Manufacturing Inc. and a sister company use Intuit's QuickBase for database services, Batchbook for contact management, and Google's Gmail and Google Docs for e-mail and document management, all at an annual cost of about $3,600.
L&L President Stephen Lewicki said the services have improved workflow and collaboration. But he also says much of the benefit is indirect and intangible - including a reduction in technology hassles at businesses where few employees have high-tech skills.
"There are certain things that I can do in the cloud that are much more efficient," Lewicki said. "And it never breaks, so I never have to worry about it."
Explore further: Sun Microsystems to offer 'public cloud' service