Needless to say, publishers were worried. In response to Struhárik’s story, the head of Facebook’s News Feed, Adam Mosseri, responded to him on Twitter. “This image reflects a test in Slovakia, Sri Lanka, Serbia, Bolivia, Guatemala and Cambodia,” Mosseri wrote. “It’s not global and there are no plans to be.”

When Struhárik followed up to ask how long the test would take—“days, weeks, months”—Mosseri replied, “Likely months as it can take that long for people to adapt, but we’ll be looking to improve the experience in the meantime.”

Publishers outside these six countries could breathe a sigh of relief. The effect of this kind of drop in traffic, particularly in the fourth quarter, when many (American) publishers have sold through a higher percentage of their “inventory,” would be devastating.

But for those inside those countries, newsrooms were, to put it gently, freaking out.

Marko Miletić works for the Serbian site Mašina, which saw its Facebook pages reach 58 percent fewer users last week as the test began to roll out, and 72 percent fewer interactions. “We don’t know how long this test will last but it can influence informational and political pluralism (at least the amount that existed on social network),” he wrote to me. That’s because, as he sees it, Facebook’s organic tools are all that smaller media publishers and “grassroots political initiatives” have. They can’t afford to pay for distribution on Facebook by “boosting” posts.

“Small (usually political-alternative) media or citizens’ initiatives, activist campaigns, solidarity actions, etc. that don't have enough money for sponsoring posts will have hard time to reach people through Facebook, which is their main tool of dispersion,” Miletić said.

Other publishers are trying to put a happier face on the changes, or at least withholding immediate judgment.

“It’s too early to say anything definitive about the impact this is having on our traffic and reach,” Jenni Reid, the web editor at The Phnom Penh Post, told me. “The two feeds still don’t seem to be fully separated yet for some people here in Cambodia, but so far it doesn’t look positive.”

Reid, who was a social-media editor for The Economist before her current position, said that it was hard to imagine how the Facebook change might positively affect their number of readers. “In its current format, it seems hard for me to see how the Explore Feed could be anything other than bad news for publishers,” she said. “It seems a strange move given that Facebook has been trying to build bridges with news organizations since the start of the year through the Facebook Journalism Project.”

These changes are significant for the broader media ecosystem in Cambodia, Reid said. “Last year, Facebook edged ahead of television as the number-one source of news for Cambodians according to one survey. Post Khmer, the Khmer-language Facebook page for the Phnom Penh Post, has the fourth-most likes in the country, and seven out of 10 of the most popular Facebook pages here are news websites or newspapers,” she told me. “That’s striking compared to, say, the United States, where there isn’t even a news publisher in the top 50 most popular pages among Facebook users.”