"Google Gears is just a natural extension of the kinds of functionality we need in browsers to continue to make our applications work really well," Sergey Brin, Google's co-founder, told CNBC's Jane Wells.
By bridging the gulf between new Web services and the older world of desktop software, where any data changes are stored locally on users' machines, Google is pushing the Web into whole new spheres of activity and posing a challenge to rival Microsoft , leader in the desktop software era.
"The Web is great but it doesn't work very well when you don't have a Web connection," Jeff Huber, Google's vice president of engineering, said in an interview. "Gears addresses a functional gap on the Web."
Google plans to make the Gears technology available for free as "open source" software, meaning other developers are free to use and enhance the software in their own products.
Gears promises to expand the usage of scores of Google products and services, as well as thousands of programs from independent software makers, by making them more accessible at previously inconvenient times and places.
The technology also allows developers to build Internet search and indexing of Web pages into their own software applications, Huber said.
Many such products will be able to make limited searches offline, since they will have downloaded data automatically when connected. Google's full Web search functions would return once the user reconnects to the Internet.
Early partners who will use Gears in their products include design software leader Adobe Systems , maker of Flash animation and Acrobat document-sharing software, as well as new Apollo tools that work online and offline, Adobe said.
Other organizations working with Google are Norway's Opera Software, maker of a Web browser popular with mobile phone users, and Mozilla, the group behind Firefox, the biggest alternative to Microsoft's Internet Explorer browser, according to Google.
Analysts said Google's move capitalizes on a growing trend over the past couple of years for Web applications to behave as responsively as desktop software.
Microsoft already offers technologies like Groove, which allows users to work offline, then synchronize changes when connected later. But the software giant has been reluctant to make existing products work both online and offline.
"Now the Web is becoming so good that there is less and less of a reason to build software that just runs on desktop computers," said Gartner analyst David Smith of Bedford, New Hampshire. "In the past, developers had to make some pretty clear trade-offs between the Web and software for desktops."
Google Gears promises to help further close the gap for software developers across the industry. "This is a very big step, but I would say it is an obvious step," Huber said.
The first Google product to feature Gears will be Google Reader, which allows consumers automatically to track updates to hundreds of Web sites. Users could connect temporarily for updates, then go offline and read up on recent Web news.
"We expect this to be extended to other Google applications over time," Huber said, without setting any timeframes.
Once retrofitted, for example, Google Apps, the company's free, advertising-supported group of Web programs including word processing and spreadsheets that can be shared and edited by groups, could work with only periodic Web connections.
Huber said Gears' biggest impact could be in parts of Africa, Asia and Latin America, where poor or non-existent Internet connections hobble access to digital information.
Google made the announcement ahead of its Google Developer Day conference, which is taking place Thursday in 10 cities around the world starting in Sydney and culminating at the San Jose Convention Center in Silicon Valley later in the day.