The digital world loves to revel in its own jargon, and one of its most popular phrases today is 'cloud computing.' You see the expression everywhere new uses for the Internet are discussed. But what do techies and companies mean when they refer to doing things in 'the cloud'? They aren't talking about meteorology, and all they see when they use the term -- which is always singular -- is sunshine, not rain.

To help you navigate through the talk about cloud computing, here's a very basic explainer. It doesn't cover every detail current among Internet experts. But I hope it gives regular folks a better understanding of the 'cloud' products and services being offered them.

At its most basic level, the 'cloud' is simply the Internet, or the vast array of servers around the world that comprise it. When people say a digital document is stored, or a digital task is being performed in the cloud, they mean that the file or application lives on a server you access over an Internet connection, via a Web browser or app, rather than on 'local' devices, like your computer or smartphone.

This isn't a new idea. For years, there have been services that would back up your files to a distant server over the Internet or keep your photos online. And Web-based email programs, like Yahoo Mail or Hotmail, are familiar examples of cloud-based applications. These programs live on servers, not your PC, and you access them through a Web browser.

What's changed is that, in recent years, large scale Internet-based storage has gotten cheaper, so it's possible for programmers to create more sophisticated remote software, and Internet connections have improved. Also, some users have expressed a desire to share and collaborate in easier and richer ways than emailing files. Cloud-based services let many users view, comment on, and edit the same material. All this has given a boost to cloud computing.

On top of that, computers are changing in ways that make cloud services more desirable. Your little netbook may lack the huge hard disk needed to hold all your music or photos, but there are ways to keep this material in the cloud and access it at will. A smartphone can't run all the sophisticated programs, or store all the files, that a PC can. But, if it's connected to cloud storage and cloud-based apps, it can do much more than its hardware specs suggest. And, with cloud file storage and apps, you could conceivably travel without any computer. A borrowed PC, tablet or smartphone might be all you need to log in and work.

So, in recent years, a flood of cloud-based products and services have appeared to store and share files; to keep data on all your devices synchronized; and to perform tasks, like editing photos, or creating and editing large files.

For instance, I wrote parts of this column in a private test edition of a cloud-based version of Microsoft Word that the company will release soon. In fact, Microsoft will be making its entire Office suite available free in the cloud. Google and others already have such cloud-based productivity suites. Another example: Many of the 200,000 apps for Apple's iPhone are merely small programs that tap data or services stored in the cloud to provide everything from restaurant choices to driving directions.

There are other good examples. At Picnik.com, you'll find an elegant, versatile cloud-based photo editor that can work on pictures from a wide variety of Web-based photo sites as well as those on your own hard disk. At Zoho.com, you'll find a cornucopia of cloud-based apps that interact with both the Web and your local hard disk. You can track your finances using a cloud-based program called Mint, which is available from a PC browser, or from an iPhone or Android-based phone.

Of course, clever readers will have noticed that this trend toward cloud computing has an obvious flaw. If you aren't connected to the Internet -- or are saddled with a poor connection -- you could be left high and dry when you want access to an important file stored remotely, or need to use a cloud-based program. Google, which is building an entire cloud-based operating system, and other companies have come up with ways to store some remote material on your local device. But these solutions aren't yet comprehensive, so wise users will make sure that the tools and files they need most are still available on their devices.

Some products get around this by offeringhybrid cloud and local services. One of my favorites in this category is SugarSync, which backs up key folders you select to the Web and synchronizes them to the hard disks on your PCs or Macs, so you always have the freshest copies handy, whether you have a connection or not. Another problem is privacy. Many of these cloud services have good security, but prying hackers are relentless, so consumers should be careful about what they store in the cloud. You may not care if a photo is swiped, but your Social Security number is a different matter.

Cloud computing is here, and growing, and quite useful. It will only get better and better.

Walter S. Mossberg

• sunshine [´sʌnʃain] n.日光，阳光 (初中英语单词)
• application [,æpli´keiʃən] n.申请；申请书；应用 (初中英语单词)
• connection [kə´nekʃən] n.联系；关系；联运 (初中英语单词)
• computer [kəm´pju:tə] n.计算机；电子计算器 (初中英语单词)
• remote [ri´məut] a.遥远的；偏僻的 (初中英语单词)
• comment [´kɔment] n.&v.评论；评注；注意 (初中英语单词)
• desirable [di´zaiərəbəl] a.向往的；极好的 (初中英语单词)
• instance [´instəns] n.例子，实例，例证 (初中英语单词)
• column [´kɔləm] n.柱；柱状物；纵队 (初中英语单词)
• release [ri´li:s] vt&n.释放；放松；赦免 (初中英语单词)
• available [ə´veiləbəl] a.可用的；有效的 (初中英语单词)
• restaurant [´restərɔnt] n.饭店，菜馆 (初中英语单词)
• variety [və´raiəti] n.变化；多样(性)；种类 (初中英语单词)
• program [´prəugræm] n.说明v.为...安排节目 (初中英语单词)
• obvious [´ɔbviəs] a.明显的；显而易见的 (初中英语单词)
• system [´sistəm] n.系统，体系，制度 (初中英语单词)
• device [di´vais] n.装置；器具；策略 (初中英语单词)
• security [si´kjuəriti] n.安全；证券；抵押品 (初中英语单词)
• singular [´siŋgjulə] a.单一的；非凡的 (高中英语单词)
• comprise [kəm´praiz] vt.包含；构成 (高中英语单词)
• document [´dɔkjumənt] n.公文；文件；证件 (高中英语单词)
• access [´ækses] n.接近；通路；进入 (高中英语单词)
• storage [´stɔ:ridʒ] n.贮存；存储器 (高中英语单词)
• tablet [´tæblit] n.碑；牌；匾额 (高中英语单词)
• edition [i´diʃən] n.版本；很相似的 (高中英语单词)
• elegant [´eligənt] a.文雅的；优美的 (高中英语单词)
• comprehensive [,kɔmpri´hensiv] a.综合的；理解的 (高中英语单词)
• offering [´ɔfəriŋ] n.提供；礼物；捐献 (高中英语单词)
• gotten [´gɔtn] get的过去分词 (英语四级单词)
• hardware [´hɑ:dweə] n.五金器皿 (英语四级单词)
• version [´və:ʃən, ´və:rʒən] n.翻译；说明；译本 (英语四级单词)
• privacy [´praivəsi, -pri] n.隐退；独处；秘密 (英语四级单词)
• hybrid [´haibrid] n.杂种；混合物 (英语六级单词)
• category [´kætigəri] n.种类；部属；范畴 (英语六级单词)
• relentless [ri´lentləs] a.无情的；坚韧的 (英语六级单词)