The closely held search-engine company has been clear all along about its goal of organizing the world's information.

But followers of the Mountain View, Calif., upstart have been seeing that lofty mission statement in a new light since the company unveiled plans this month for a free e-mail service with enough storage space to save nearly 500,000 pages of messages.

The Gmail service, combined with Google's enormous cluster of computers that use Linux, a free operating system, to process hundreds of millions of search queries each day, has some technologists panting over what the ambitious company may do next.

"Who needs Windows when anyone can have free unlimited access to the world's fastest computer running the smartest operating system?" Jason Kottke, a New York City Web designer, wrote in his influential Web log at Kottke.org.

Google executives declined to comment on their plans.

By all accounts, Google isn't openly gunning for Microsoft.

Netscape Communications Corp., whose Web browser threatened Windows, made that mistake in the late 1990s and got smothered by Microsoft's tactics, which a federal judge later found violated antitrust laws.

Google, however, has been quietly building one of the world's largest supercomputers, reportedly made of more than 100,000 servers tied together by Linux. The computing system is becoming a powerful platform that could be put to a variety of uses beyond powering the most popular search engine on the Web.

"I wouldn't underestimate the audacity of any of the goals the Google guys have," said Rich Skrenta, chief executive of a search engine for news called Topix.net. "They're big thinkers."

Google has expanded its offerings to include news aggregation, comparison shopping, software for publishing Web logs, a social networking service called Orkut, and now Gmail.

Many believe Google's next step will be to use its unmatched processing and storage capacity to invite people to house things on Google's network that they normally keep on their computer desktops, such as documents, digital photos, spreadsheets and songs. All of those files would be accessible from any Internet-connected device and easily searchable using the technology that made Google famous.

That could mean trouble for Microsoft. The more you can do on the Internet, the less important your PC becomes. Microsoft Chairman Bill Gates has been worrying about the Internet making Windows less relevant since 1995.

Microsoft executives declined to comment on the threat from Google or on plans of its own.

John Battelle, a co-founder of Wired magazine who is writing a book on Internet searching, said he could envision a Google word processor that comes with the Google toolbar for Internet browsers. Documents could be stored on Google's servers, which would allow writers to query Bartlett's Quotations, Dictionary.com and other sites while they type.

Kottke and Danny Sullivan, editor of Search Engine Watch, said Google should even be thinking about selling a Google PC. It could run a version of Linux with Google's search technology built in and include an open-source alternative to the Microsoft Office suite of business software. After all, they note, Google sells a server computer, the Google Search Appliance, that lets companies search their internal or public Web sites.

Just because Google could feasibly market its own computer or desktop software, of course, doesn't mean it will.

In part, the decision depends on the success — or failure — of Gmail. Google plans to pay for the free e-mail storage by scanning messages, then displaying an ad related to the contents.

Privacy advocates have criticized the practice, and it remains to be seen whether consumers will accept it.

If Google executives intend to expand their online offerings or get into the PC business, it wouldn't be wise for them to say so and risk baiting the world's most powerful software company.

"If they had made that decision, it's entirely in their best interest not to tell anybody," Battelle said.