The Changemakers chatboards buzzed. Hundreds of contestants from 29 countries had gathered online to compete for $5,000 cash prizes and the potential for millions more. Fans logged in around the clock to cheer their favorites and vote for a winner.

"Simply mind-blowing," raved one fan from India about one of the entries. "Long live Joyce!" wrote another from Uganda, referring to a different entry.

It sounds like an American Idol knock-off, but the goal here wasn't to crown another pop star. The organizers at Changemakers, a philanthropic foundation, wanted ideas on how to improve poor people's access to health care. In the end, the winning entries included a plan for creating a computer network that allows medical specialists to help rural doctors treat chronic diseases and a model for setting up family-counseling clinics in shopping malls.

Welcome to the latest craze in philanthropy: competitions. Trying to shake up the traditionally exclusive and opaque process of grant-making, benefactors ranging from the Rockefeller Foundation to Virgin's Sir Richard Branson are funding public contests aimed at solving the world's ills. While these competitions sometimes fall short of generating viable solutions to the problems they seek to address, they're drawing plenty of publicity, money, and ideas to causes that usually draw resigned sighs.

"Can I tell you that more children are being fed somewhere, or health has improved [directly] because of a Changemakers competition? No," says Nancy Barrand, a senior program officer at the $10 billion Robert Wood Johnson Foundation, which sponsored the Changemakers health-care competition and is considering entrants for $5 million in grants. "But if you believe that change comes from making more people aware of a problem and bringing more resources to bear on that problem, then I think Changemakers does have an impact."

In many ways, publicity is the most valuable by-product offered by competitions—not only for the causes and the foundations that champion them, but also on those laboring away in the trenches to help solve them.

Diane Flannery, the co-director of the Semel Institute at U.C.L.A. who won one of the prizes in the Changemakers health-care competition for her proposal for accessible family counseling, says the contest gave her team a whole new level of exposure, putting her in touch with many potential funders and collaborators.

"We got called by people at U.C.L.A. who didn't even know what we were doing and were interested in our work," recalls Flannery, who says she was initially skeptical about philanthropic competitions.

Competitions to spur innovation and do social good aren't new—Charles Lindbergh's 1927 transatlantic flight was famously the result of a $25,000 competition that helped spur the growth of commercial air travel—but the sheer range and number of competitions being put together is.