Ah, the Russian trolls.
I run a crowdsourced news startup (https://grasswire.com), and along with it one of the bigger non-mainstream news Twitter accounts (@grasswire, 130k followers).
The Ukrainian conflict has died down a little bit, but when it was in full swing the Russian trolls were everywhere, and were pretty obvious, but that didn't matter.
For example, here are a couple of my favorites (and among the most active:)
https://twitter.com/gogigogi12
https://twitter.com/steiner1776
I'm pretty sure now they're mostly set to automatically retweet anything with a pro-Russian sentiment, but back in the day they would pretty much respond to every tweet. For the casual user it was very convincing stuff: "Oh wow, maybe @steiner1776 is right and that report was full of lies, and I just didn't know better - thank goodness I have someone who is willing to stand up for truth."
Most people don't have time to research, and just follow public opinion, even if the public opinion is created by a bunch of trolls. It's especially easy to fall for the trolls when they tell you that "the man" has been lying to you all along (and in most cases "the man" means the United States). (To be clear: The United States does some messed up stuff and is far, far from without fault.)
There were a few days when they would seemingly download photos from any tragedy that had ever happened, and just add a generic line - something like "Stop killing Donbass people," insinuating that these deaths were caused by the Ukrainian army (and by extension, somehow, the United States). The photos were from Syria, Iraq, Palestine, Israel - wherever. I'm sure they were just being pulled from some file somewhere with a generic message attached. But that stuff _exploded_. Hundreds of thousands of retweets per day, driving public opinion, based on complete and utter bullshit.
So there are some Russian trolls; this isn't the end of the world, right? The problem is that for many of the people on Twitter these were real people expressing legitimate concern. Some of their blatantly false tweets (they were easily discoverable to be such with a reverse image search) went legitimately viral (not just spun into their other accounts for retweets). Hundreds of thousands of impressions per tweet from people who aren't going to run a reverse image search, and get their news from Twitter.
I don't know what the solution is, but this is extremely dangerous for society. It's easy to pass them off as "trolls," but trolls change the way that people act and believe, even when they're only sharing false information.
We started Grasswire in part as a response to that. The fact-check feature on Grasswire isn't used as frequently now, but at the time about 50% of the stuff that went viral was completely and verifiably false - look at the history of the Grasswire Fact-Check account (@grasswirefacts) for examples of that. It helped, but I fear it was only drop in the bucket.