Facebook founder Mark Zuckerberg and Microsoft billionaire Bill Gates have thrown their weight and resources behind the goal of bringing internet access to everyone in the world by 2020.
The pledge is part of a United Nations effort to eradicate extreme poverty by 2030, a goal set on Friday during a special summit at the global body.
The internet became commonplace in developed countries in the 1990s, but UN officials estimate that half the world does not have reliable access - especially women and girls, whose education is vital to development.
"When people have access to the tools and knowledge of the internet, they have access to opportunities that make life better for all of us," said a declaration signed by Zuckerberg and Bill and Melinda Gates, who have devoted their wealth to philanthropy.
"The internet belongs to everyone. It should be accessible by everyone," the declaration said.
Zuckerberg, writing on Facebook, said that for every 10 people connected to the internet, one is lifted out of poverty.
"If we connect the more than four billion people not yet online, we have a historic opportunity to lift the entire world in the coming decades," he wrote.
Other signatories included Jimmy Wales, co-founder of free online encyclopedia Wikipedia, and U2 frontman Bono on behalf of his One anti-poverty campaign.
The Bill and Melinda Gates Foundation on Saturday launched its own roadmap, which put a top priority on improving the health and education for girls.