MOUNTAIN VIEW, Calif. — Microsoft Corp. increased its Silicon Valley presence Monday by launching a new technology center that the software titan hopes will help its expansive new strategy for Internet-based services.

Microsoft has housed some divisions in the area for years and has 1,500 employees here, but the vast majority of operations are based in Redmond, Wash. Microsoft Chairman Bill Gates, making a rare public appearance in the valley, and other company executives stressed the company needs partners here.

"We're learning an amazing amount from this community of talented individuals by really, really listening to them," CEO Steve Ballmer said in a videotaped address.

The new center is ostensibly a research lab where e-commerce companies can spend two weeks to two months testing the usefulness and reliability of their software applications. Microsoft also runs similar labs in Toronto, Boston and Austin, Texas; one is scheduled to open in Chicago this spring.

The Mountain View lab has the added benefit of putting Microsoft in closer contact with software developers and technology gurus at other companies who must be involved if Microsoft is to enact its broad Web-services strategy, known as .Net (pronounced "dot-net").

"Only if we get literally tens of thousands of people to do work around .Net will it achieve a critical mass," Gates told 1,000 people packed into a large white tent on the center grounds. "This will be measured by how many .Net solutions we can build here."

Microsoft executives said the center, which will employ 30 to 50 people, cost more than $10 million without being more precise. Unisys Corp. and Compaq Computer Corp. also have invested in the center and provided servers.

"I think it's a pivotal position for Microsoft in the sense that this will be the place where a great deal of the .Net applications will be developed and tested," said technology analyst Tim Bajarin, president of Creative Strategies Inc. "They recognize that Silicon Valley is at the heart of where a great deal of next-generation technology development takes place."

Gates described .Net as a vision that PCs, handheld computers and new hybrids could work together better to share information. He said .Net would be as important to the next phase of computing as the DOS operating system was to early personal computers and Windows was to the next era.

He dismissed the suggestion that such talk was the same kind of hype about the Internet that was deflated in the recent dot-com collapse.

"Although there were excesses in some of the things that took place, the dream is very much alive," Gates said. "And the breakthroughs in hardware and software are going to go even beyond what was expected."