Facebook’s Apps Went Down. The World Saw How Much It Runs on Them.

In Latin America, Facebook’s apps can be literal lifelines in rural places where cellphone service has yet to arrive but the internet is available, and in poor communities where people cannot afford mobile data but can find a free internet connection.

Cosas de Mujeres, the nonprofit in Colombia, has hundreds of interactions every month with Colombian women and Venezuelan migrant women who face domestic and emotional violence or are at risk of trafficking or sexual exploitation, said Ms. Berryhill, the organization’s director of digital operations.

“WhatsApp is a very important tool for our service,” she said. “Usually we have phone operators receiving messages from women all day via WhatsApp, but that was not possible, and women could not contact us.”

María Elena Divas, a 51-year-old Venezuelan migrant in Bogotá, Colombia, uses WhatsApp to take orders for snacks like empanadas.

“I didn’t sell anything today,” Ms. Divas said. “It was a hard day for everyone like me.”

Across Africa, Facebook’s apps are so popular that for many, they are the internet. The company has stuck deals with many carriers to make its services accessible on phones without data charges.

WhatsApp, easily the continent’s most popular messaging app, has become an effective one-stop shop for people to communicate with friends, colleagues, businesses, fellow worshipers and neighbors.

In Kenya’s capital, Nairobi, anything from shoes and jewelry to plants and household appliances can be ordered for delivery from Facebook, Instagram and WhatsApp. In Johannesburg, vendors were cut off from Facebook Marketplace, which is used to sell everything from used cars to wigs and even corrugated iron shacks, known colloquially as zozos.