When staffers at GitHub first saw the email from a Russian agency claiming dominion over the internet last month, they didn’t take it seriously. GitHub operates an enormously popular site where computer programmers share and collaborate on code, and to the Silicon Valley startup, an email requesting the removal of a list of suicide techniques from the site just didn’t seem believable.

But GitHub is a place where you can post almost anything—not just code. On a handful of GitHub pages, someone had indeed cataloged the pros and cons of different suicide techniques (with the “pistol,” the drawback was “Time: From the fractions of a second to several minutes if bad aim). And the Russian agency was dead serious about wanting to take these pages down. Last week, after GitHub failed to remove the links, its service was blocked in Russia.

The outage lasted only a day, but it holds broader implications for US companies hoping to do business in Russia. Call it a minor skirmish in Russia’s larger battle to build a Kremlin firewall around the internet. Today, the Russian government is trying censor individual pages served from overseas, but a recently passed law could eventually prevent foreign internet companies from reaching Russia unless they set up computer servers inside the country, a setup that would leave them very much at the mercy of the local government—and not only in terms of censorship.

It’s a battle that threatens to put Russia on par with China—a world power whose people experience a downgraded and closed online experience. Unlike China, however, censorship on the Russian internet is a relatively recent phenomenon, says Eva Galpern, a global policy analyst with the Electronic Frontier Foundation. “For a couple of decades, they’ve actually had a relatively free internet,” she says.

Beware the Roskomnadzor

That all changed in the summer of 2012—a year after Moscow’s streets were rocked by protests. That’s when Russia created the Roskomnadzor.1 Over the past two years, the agency has built out the muscle and infrastructure to take down anything it doesn’t like. It administers a central blacklist of blocked sites, used by Russian internet service providers to manage the Kremlin firewall.

“We should inform you that the URL…contains information which has been recognized by Federal service on customers’ rights protection and human well-being surveillance (ROSPOTREBNADZOR) as prohibited on the territory of the Russdan Federation,” read the email the agency sent GitHub on October 21.

In March, the Roskomnadzor cut off access to websites run by Putin critics Alexei Navalny and Garry Kasparov. But it’s been harder for the agency to vaporize the instantly forkable GitHub suicide pages. Since news of GitHub’s one-day outage went public last week, hundreds of new pages, including virtually identical content have sprung up on the website. The agency did not respond to WIRED’s request for comment.

Ostensibly, the Roskomnadzor’s blacklist is there to keep what Russia considers to be dangerous content from the internet—things like suicide instructions, drug cookbooks, and information about terrorist organizations. But critics see it as a first step toward shuttering dissent. “What we have discovered, of course, is because there is no accountability for who gets added to this blacklist,” says the EFF’s Galperin, “they blocked pretty much all of the major independent news sites.”

The Near-Impossible Task

At the same time, says Andrei Soldatov, an investigative journalist who runs the website Agentura.Ru, the government’s long-term goal is to force companies U.S. companies to move their online operations into Russia. This year, the State Duma passed a law that would force foreign companies such as GitHub, Google, and Twitter to use servers located within the country when storing data from local users. It’s set to take effect next year.

If their servers are in Russia, that would mean even stricter censorship for U.S. companies. But, as Soldatov explains, it would also open these companies to surveillance by Russia’s Federal Security Service, known as the FSB. The more likely outcome is that, if Russia clamps down on U.S. companies, some just won’t play in the country. Indeed, the Wall Street Journal described the situation as a “near-impossible challenge for US-based firms that have millions of Russian users but generally store data on servers outside the country.”

According to Galperin, this could drive US companies out of Russia by 2016. “We’ve essentially gone from let’s protect the children,” she says, “to let’s block news sites; let’s block independent journalism; let’s block political opponents, and—in the future—let’s block all services that might host content that might be potentially problematic.”

1Correction: 11:20 EST 12-10-2014 This story has been updated to correct the spelling of the Russian agency, Roskomnadzor.