Apple founder Steve Jobs announced a free service Monday that allows consumers to store vast amounts of music, video, photos and documents on the Web, one of several emerging “cloud” computing offerings that are diminishing the need for a computer.

Once a pioneer of the personal computer, Jobs forecast that his new iCloud service would replace the PC as the hub for people’s multimedia needs, making it far easier for them to gain access to their digital libraries on phones, tablets and a multitude of other devices that have an Internet connection.

“Keeping these devices in sync is driving us crazy,” he said at a company conference in San Francisco. “We have a great solution for this problem. We are going to demote the PC to just be a device.”

The irony of Jobs’s statements was not lost on analysts who noted his role in putting a PC into nearly every household in the country.

“The whole idea of a standalone personal computer with a big processor is going the way of the VCR,” said Paul Saffo, managing director of foresight at Discern Analytics. “Steve Jobs, who delivered personal computing to the rest of us, is now doing more through the iCloud to get rid of personal computing than anyone.”

A wave of new technologies such as cloud computing is shuffling the industry’s leaders, elevating the likes of Apple, Amazon and Google while forcing once-dominant companies such as Microsoft and Dell to reinvent themselves to keep up.

Saffo added that some of those companies haven’t quite figured it out. Founder Michael Dell was rehired at Dell largely to deal with the emergence of the cloud, Saffo said, and Microsoft is just “stumbling.”

“It’s a rough transition for those used to selling keyboards,” he said.

While cloud computing offers convenience — Apple gives a user access to the same songs and files on up to 10 devices virtually anywhere — the technology could make personal data less secure, some analysts said. Most consumers already use the cloud, whether they know it or not, through Gmail, Facebook, the Kindle, or the photo-sharing Web site Flickr.

Chris Calabrese of the American Civil Liberties Union said privacy laws that apply to cloud computing are out of date. “It’s not like putting your data in a desk drawer,” he said. Although the government needs a judge’s order to seize a hard drive, a subpoena is often enough authority to obtain cloud data, he said.

Companies also have a lot of access to personal data. Amazon’s Kindle, an electronic book reader that relies on cloud computing, is “a microcosm of promise and perils of the cloud,” Saffo said.

“The company doesn’t just know what you read, but how long you spend on a particular page. The cloud knows more about you than you know,” he said. “Information we want to have lost will hang around a lot longer than we imagine.”

That’s not dissuading government agencies from embracing cloud computing. A recent report issued by the Office of Management and Budget said 25 agencies have listed 78 applications to move to the cloud within the year. Many agencies, including the Department of Homeland Security and the Justice Department are moving services such as e-mail to the cloud, said Paul Garver, chief executive of Quest Software.

Not all of them have contingency plans. In a recent Quest Software survey, more than 90 percent of federal agencies that use the cloud in some capacity said they didn’t know how to remove their data if something went wrong.

The cloud is also susceptible to crashes. When Amazon’s cloud servers went down last month, multiple Web sites crashed, and in February, thousands of Gmail users temporarily lost e-mails after an outage.

But Dan Pitt, executive director of the Open Networking Foundation, a nonprofit that looks at cloud computing, hopes that problems will be ironed out.

“I think we’ll get there. Cloud computing is going to become ubiquitous. Even if consumers don’t know it,” he said.

Jobs touted the advantages of his firm’s cloud services over competitors. For one, Apple has sealed deals with several music companies, so customers can access songs on the cloud without having to upload their library. Apple’s offering is also free, unlike Amazon’s, which charges $50 for 50 gigabytes. Apple allows a maximum of five gigabytes, but doesn’t count songs, apps, photos and iBooks toward that limit.

For about $25 a year, Apple will allow users to access songs they own but were not purchased through iTunes.

Jobs said iCloud will run with iWork, its office suite, putting it in direct competition with Microsoft’s dominant Office Suite and Google’s suite of basic office Web applications.