"Joshua Fisher-Birch, a researcher at the Counter Extremism Project, said that Tarrant’s so-called manifesto was full of in-jokes and memes from internet and gaming culture. He referenced a dance from the game Fortnite, and joked that one old PlayStation game had 'taught [him] ethnonationalism.' Before getting out of his car and launching the attack, Tarrant told his livestream followers to subscribe to the popular YouTuber PewDiePie."