But a central element of his Internet.Org campaign was controversial even before it was shut down in a key market this month.
Indian regulators banned one of the pillars of the campaign, a service known as Free Basics, because it provided access only to certain pre-approved services including Facebook rather than the full Internet.
That leaves the social media mogul at a crossroads. Though he has vowed not to give up, Zuckerberg hasn't said whether he'll alter his approach. Facebook declined to make executives available for comment.
"Everyone in the world should have access to the Internet," Zuckerberg wrote on Facebook this month, arguing that online connections can improve lives and fuel economic development.
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To achieve that goal, Zuckerberg has high-flying dreams for someday providing Internet connections through a network of drones, satellites and lasers.
But his near-term plan is simpler: Facebook works with wireless carriers in poorer nations to let people use streamlined versions of Facebook and certain other online services, without paying data charges.
A low-income resident of urban Manila, for example, can use Free Basics to view the Philippines' GMA News site. "He can be informed. He can research. He can read the news," Ederic Eder of GMA News said.
The program varies by country, in offerings and effectiveness.
In South Africa, for instance, Facebook partnered with the third-largest wireless carrier, Cell C. But Johannesburg resident Priscilla de Klerk said she couldn't get Free Basics to work on her phone.