They also gained attention for “boomer memes” — low-quality, scrappily produced ads that reiterate simple messages by pasting them onto images from popular shows like “Game of Thrones.”
Their approach is to find ways to attract attention to their clients, whether candidates or parties, by pushing emotional buttons that elicit a response online. “We’re talking anger, excitement, pride, fear,” Mr. Guerin said at a conference in June. “Your content should be relating to one of these emotions for anyone to give a damn about it.”
He described the strategy as “How do you win the battle of the thumbs?”
For all of the effort and attention devoted to it, disinformation’s overall influence on voters is far from clear. Researchers have struggled to precisely measure how much people are swayed by what they see in their social media feeds.
In Wigan, a longtime Labour stronghold in northwestern England where the Conservatives have been trying to capitalize on strong pro-Brexit sentiments, newspapers and television remain a common way for many people to get information. But for others, like Greg Rimmer, a 26-year-old who works for the local government, everything comes from social media.
Pulling out his phone, he scrolled through a Twitter feed filled with political posts criticizing the Conservative Party’s health care plans. He tapped over to Facebook, where he saw another meme about the election.
“I hardly ever watch the news, but I’m on Facebook, Twitter, Instagram and YouTube all the time,” he said. “I try not to let it sway me, but if you see something constantly, you can’t help it.”
Many videos shared on Facebook and in WhatsApp groups around the country originate in a cramped office in the northern London neighborhood of Finsbury Park.