That kind of a quip is vintage Gates--analytically, if not politically, correct. It's also an indication that the traits that brought him success in business are the same ones he will bring to philanthropy.

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So what have we seen him do in the past? If you ask his competitors, Gates has been known for the ruthless annihilation of adversaries--and a tendency to declare victory perhaps a bit early.

Happily, this is a time when we can root for Gates to decimate his foes. Instead of companies, he's going after Big Problems: diseases that kill children, illiteracy, hunger.

Of course even if the Bill & Melinda Gates Foundation winds up spending about $100 million--roughly the combination of its current assets along with the existing fortunes of the Gates family and pal Warren Buffett--the problems Gates is tackling are achingly big.

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So there's that tendency to declare victory. When you're selling products to customers, it's great to announce that your product is at the top of the charts. Make the point loudly and frequently and people start to believe you. New customers buy more of your stuff.

What problems will Gates be able to declare he's solved first? And what will happen when he does? Diseases don't care if you claim that they are under control: Relax vigilance and the evil roars back to strength.

The disease that could give the Gates Foundation a great opportunity for a big press release is malaria. Everything about malaria is evil: It kills at least a million children a year, mostly in Africa. The parasite that causes the disease has been wily enough to evade eradication attempts in the past--from the Rockefeller Foundation's efforts in the early 1900s, to the World Health Organization in the 1950s. It has built up immunities to the cheapest treatments. It literally sucks the vitality and life out of emerging economies. By the early 1990s, worldwide funding on malaria research had practically dried up.

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The Gates couple began handing out research grants for malaria in late 1998, even before they had formalised the structure of their foundation. Since then, they have poured more than $860 million into just malaria research and another $650 million into the Global Fund for fighting AIDS, tuberculosis and malaria.

Much of the money has gone for researching the kind of high-impact, high-tech solutions, such as a malaria vaccine, that attract Gates' most passionate enthusiasm. (Long-time Gates friend, Nathan Myhrvold is helping out by funding research on what is the most out-of-the-box way to deal a blow to malaria: adapting high-power laser technology originally developed for the Strategic Defense Initiative to find and zap the mosquitoes carrying the malaria parasite.)

Critics argued that simpler, low-tech solutions could save lives too.

And, taking a different path than Microsoft had traditionally trod, the Gates Foundation took the hint.

Beginning around 2005, the foundation began experimenting with programs providing the most basic solution--bed nets laced with insecticide. It has put $64 million toward a program for distributing bed nets that started in Zambia and is expanding to other African countries. It's working with a spectrum of other organisations to raise awareness and funds for bed nets. The Gates Foundation is the biggest malaria funder on the world block, but it's trying to cooperate with the other players as well.

Perhaps the most telling indication of the change in the signature Gates swagger is how the foundation handled one of its first big "solution" announcements: About three years ago, the foundation issued a press release declaring that it had provided at least one computer to every library in America.

In the old Microsoft days, that kind of press release would have been celebrated as a gala event. Problem solved.

The foundation was more circumspect. It publicised the news, but at the same time, it pointed out the next challenge--providing computers to libraries in North America, followed by the northern hemisphere.

As Gates builds his career in philanthropy, he will want to declare victories. But if the first indications are true, the foundation that he and Melinda are building will not just declare success and move on. It will actively seek ways to continue vigilance, recognising that the adversary can't simply be put out of business.

And in that case, we will all have reason to root for Gates--no matter how ruthlessly he goes after his new adversaries.