Basically, it is a next level of jamming techniques used against western radio stations in old times - active trolling instead of passive jamming, using paid people instead of dumb noise generators.
What Russians developed is very efficient (optimized, if you wish) set of methods to manipulate the minds of idiots, to implant naive, unverified (and unquestioned by wast majority of idiots) assumptions and false premises, in forms of emotionally charged but primitive memes (textual or graphical) - "Shillary will start WW3". Fucking degenerates.
In the same way all the Russian media propaganda is organized nowadays - meme-like framed "news", tailored to the vocabulary and mentality of uneducated, primitive majority, along with marketing-like targeting. You do not have to have a PhD to do that.
What happened is that almost everyone else nowadays are re-using these simple ready-made methods. All this is nothing but virus-like meme contagion, plus applied manipulative psychology of advertising on internet scale. That's all. No KGB agents or anything like that.
How a third-world, corruption-ridden country with stagnant economy could be so powerful? It obviously wasn't. The cause is these "information viruses" (memes) spreading through human stupidity. Russians didn't invent them, of course, only used on a large scale.