A group of maybe a dozen people can create the impression of anything between 20,000 and 40,000 tweets in an hour. They can then push that hashtag into the trending lists. It throws a smoke screen over the whole idea of one man, one vote. Somebody who controls 10,000 bots or 100,000 bots, they are controlling 100,000 voices and they distort the debate,” says Nimmo.
Source: Troll factories, bots and fake news: Inside the Wild West of social media