Tumblr has listed a number of accounts linked to Russian social media agitation giving the newest look at a sophisticated effort to sow discord between Americans — including black users.

The blogging service announced that it had discovered more than 80 accounts linked to the Internet Research Agency, the professional troll farm indicted by Justice Department special counsel Robert Mueller.

IRA workers created hundreds of social media accounts across many platforms in an effort to turn up the volume of political disputes taking place between Americans online.

That included using fake online accounts to organize real-world political events and posing as black Americans to address real black Americans discussing race, law enforcement and the 2016 political campaign.

On Tumblr, the Russians used accounts called “black-to-the-bones;” “blackness-by-your-side;” “blacknproud;” “blacktolive;” and “bleepthepolice.” Others were called “noteverythingiswhite;” “starling-all-black-all-day;” and “weproud2black.”

Still other accounts changed their names to drop or pick up apparent black affinity — one went from “blackprideworldwide” to “shoutoutworldwide;” another went from “heygeraldmartinjohanssen” to “ghettablasta” to “postingwhileblack.”

“Their goal is to sow division and discontent in the countries they target,” said a post on Tumblr’s own official blog. “What makes them so difficult to spot is that they’re not spambots. They’re real people who get trained and paid to spread propaganda.”

Tumblr sent an email to users identifying accounts with which they may have interacted, but it wasn’t clear Monday how much effect the Russian users had over the social media platform.

Last year, Tumblr was credited with around 345 million accounts and many more individual users, but there was no immediate information about what kind of total reach the Russian accounts may have had.

The largest part of the social media agitation aspect of Russia’s active measures campaign probably involved Facebook. It illustrated how a comparatively small effort can achieve larger effects across a network.

Russian influence-mongers bought a relatively small number of paid ads on Facebook and Instagram, which Facebook owns, but once they had been shared and users began seeing more free content, around 150 million people saw some Russian material, the social media giant said.

Black users and Black Lives Matter were a target on Facebook as well, according to Mueller’s indictment. The best-known account, “Blacktivist,” and others sought to divide black users from within. In another example from Mueller’s indictment, IRA influence-mongers used the Instagram account “Woke Blacks” to encourage followers not to vote for any candidate in 2016.

“[A] particular hype and hatred for Trump is misleading the people and forcing Blacks to vote Killary. We cannot resort to the lesser of two devils. Then we’d surely be better off without voting AT ALL,” a post from the account said.

This aspect of Russia’s active measures continued a decades-long practice of targeting race inside the United States.

More recently, there have been indications that influence-mongers piggybacked on real users’ protests about news coverage of the Austin bombings — which critics said got short shrift because some of its victims were black — as well as last year’s NFL protests, the violence in Charlottesville Va. and other stories.

Tumblr said that it didn’t think Russian influence-mongers bought any paid ads on its platform. The service said it discovered only human-posted and shared material and urged users to take care.

“They want to drive a wedge between us so that we spend our time fighting with each other instead of building towards the future,” Tumblr’s post said. “We’ll be watching for signs of future activity, but the best defense is knowing how they operate and how to judge the content you see.”

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