Formidable as it may be, the Bill & Melinda Gates Foundation has taken time changing the world.

Last year, in fact, it ranked only No. 7 on Barron's list of high-impact givers, even though its $34 billion in assets towered above those of all other foundations. While the Gates foundation had some mighty big irons in the fire, including efforts to develop an AIDS vaccine, the payoffs were years away. The six philanthropists ahead of the Gateses were getting large and immediate bangs for their bucks. To us, that's impact.

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