The coordinated volleys of posts are described in a research paper that will be published this year in the American Political Science Review, in which three scholars—Harvard’s Gary King, Stanford’s Jennifer Pan, and Margaret Roberts at UC San Diego—analyzed tens of thousands of posts written by China’s official social-media trolls.

The fact that the government coordinates friendly social-media posts isn’t new: The people behind them are known colloquially as the “50 Cent Party,” for the rumored sum they’re paid for each post. (They’re not actually members of a political party.) But by studying a large archive of emails leaked from one of the internet propaganda offices in Ganzhou—a city located in China’s southeastern Jiangxi province—the researchers were able to piece together details about how the operation works, and make some inferences about the campaign’s motivations.

Before setting out to research the 50 Cent Party, the scholars largely subscribed to the conventional wisdom among academics and journalists: that ordinary citizens were enlisted to debate with rabble rousers, and take a hard pro-government stance. Instead, they found very few instances of 50 Cent posts engaging in a back-and-forth, and a large volume of innocuous “cheerleading” posts that simply express goodwill about the government and its policies. Criticism on social media is largely tolerated, they found, but as soon as the risk of mobilization and collective action begins to loom, the government jumps in to disrupt the conversation.

Throughout the project, the researchers enjoyed unusual access to the inner workings of the Chinese government. The emails leaked from the Zhanggong propaganda office, for example, included the text of more than 43,000 50 Cent posts, sent from commenters proving that they’d completed their assignments, and messages from the propaganda office to higher-level offices.

The commenters themselves, it turned out, were nearly all identifiable as government workers. (There’s no evidence, the researchers said, that the government used bots to amplify its message.) They worked in various offices and bureaus, and didn’t appear to be paid at all for the posts. It may be that they were simply expected to post coordinated messages as part of their government jobs.

In emails from the propaganda office, commenters were instructed to “promote unity and stability through positive publicity,” and to “actively guide public opinion during emergency events”—where “emergency events” refer to events that might stoke collective action.

Based on what they found in the leaked archive, the researchers extrapolated the scale of the propaganda operation to the rest of China, estimating that the loosely-defined 50 Cent Party posts a total of 448 million messages on social media every year. “If these estimates are correct, a large proportion of government web site comments, and about one of every 178 social media posts on commercial sites, are fabricated by the government,” the researchers wrote.