Indonesia, home to roughly 6 percent of Facebook Inc.'s users, isn't happy with the social media giant. Officials there are even threatening to shut the service down after its latest egregious privacy scandal.

That sounds like an ominous threat — but it's empty. In Indonesia, as across the developing world, Facebook is no longer just a platform for sharing photos and news. It's becoming perhaps the world's most important channel for small businesses to reach customers. From Asia to Africa, countries are learning that they need Facebook as much as Facebook needs them — and maybe more so.

People have always bought and sold stuff on Facebook, of course, whether it's offering a couch for sale to the top bidder or joining a Buy and Sell Group devoted to Frankoma pottery. In each case, the goods are displayed, a deal is negotiated and payments are made through a third-party system or in person. In 2018, 550 million people used the platform to "buy and sell items in local communities."