As Gates' successor, Ozzie is responsible for Microsoft's technical direction and how it touches all areas of the business, particularly when it comes to the company's Web-based services vision.

His first major presentation, at Microsoft's TechEd conference in Boston in 2006 during the same month he became chief software architect, also marked the first time Microsoft outlined its "software plus services" strategy. The plan, which Microsoft is in the midst of executing, laid out how the company will gradually transition from a packaged software vendor to one that offers both software and hosted services.

Being a techie himself, Ozzie likely will continue Gates' tradition -- which has served Microsoft remarkably well -- to woo developers as a way to make an end run around companies like Google that already lead a market Microsoft wants to conquer.

In this role, Ozzie will likely excel; in a recent interview published in the Financial Times, he himself said he is "closer to the technology and products" than even Gates was.

But Ozzie may not have the business edge that Gates has -- that relentlessness to fight for an idea or a business until he is successful, no matter what collateral damage is done.

Yet this relentless streak also hurt Gates, especially once Windows became the de facto OS for the PC market and a popular developer platform for businesses, said Shane Greenstein, a professor in Northwestern University's Kellogg School of Management.

"Gates draws on an almost unique mix of drive, persistence and patience when pursuing his goals," Greenstein wrote in a two-part essay, "The Long Arc Behind Bill Gates' Wealth." "For example, he furiously drives himself to learn the things he believes he needs to know, and he will negotiate incessantly until he wins on the points he wants, but he will wait eons for results from investments."

It's unclear whether Ozzie has this same drive, Greenstein said in an interview. But a lack of obsession with one goal could actually be a strength for Ozzie, whereas it was Gates' Achilles heel.

Gates was so concerned with Windows maintaining its place in a PC-centric technology industry that he did not foresee the new advertising-based business model of the Web until it was upon him, Greenstein said.

"Bill's vision for how to exploit an opportunity -- the Internet in particular -- was rooted in his historical experience in the PC market," he said. "He was so good at that that he was unable to understand how you might develop a Web-based business model even as early as '97, '98. He didn't have the vision that a lot of the younger, newer firms had about how the Web could be used."

Greenstein suggested that Gates may even have recognized that his own flaw rendered him unable to lead Microsoft through its transformation to services and the Web, and thus decided to pass the torch to Ozzie for the good of his company.

Unlike Gates, Ozzie has already proven he knows when to walk away from a pet project to embrace technology innovation. He abandoned Lotus a few years after selling it to IBM to form Groove Networks, so he could experiment with his vision for peer-to-peer networking, which was then an emerging technology.

Groove's technology for enabling people to collaborate both online and offline has now found its way into Microsoft's Office suite; Ozzie is applying these same ideas to Microsoft's Web strategy with services like Live Mesh.