The Subscribe to PewDiePie Movement

The "Subscribe to PewDiePie" Movement was a movement conducted by an enormous amount of people to keep PewDiePie as the number 1 most subscribed YouTube channel since he was in competition with T-Series.

YouTubers
The first prominent YouTuber to support PewDiePie was MrBeast (Jimmy Donaldson), who bought billboards and radio advertisements in North Carolina urging people to subscribe to PewDiePie's channel. He also created a video of himself saying "PewDiePie" 100,000 times in a period of over 12 hours. MrBeast and his friends attended Super Bowl LIII, wearing T-shirts reading "Sub 2 PewDiePie". The group was prominently displayed in an ESPN tweet after Stephen Gostkowski had missed a field goal during the 1st quarter.

Other prominent YouTubers have publicly campaigned for subscribing to PewDiePie, while others such as Markiplier, Jacksepticeye and Logan Paul have made videos or tweets announcing their support for PewDiePie in the competition, often under the slogan, "Subscribe to PewDiePie". YouTuber Justin Roberts, a member of the group Team 10, bought a billboard in New York's Times Square saying the same. Markiplier made a tongue-in-cheek live stream titled "I literally won't shut up until you subscribe to PewDiePie" telling his viewers to subscribe to PewDiePie's channel. Jacksepticeye did a live stream telling his viewers to subscribe to PewDiePie's channel and jokingly threatened to delete his channel if T-Series surpasses PewDiePie.

Smaller Youtubers have also promoted PewDiePie. In reaction to MrBeast's advertising campaign, Saimandar Waghdhare, an independent Indian YouTuber with the channel "Saiman Says", responded to MrBeast's advertising campaign by posting a sarcastic video in which he pretends to support T-Series. However, he later released a video in which he declares his support to PewDiePie. Musician Davie504 flew from Hong Kong to Noida and played "Bitch Lasagna", PewDiePie's diss track against T-Series, outside their headquarters on a bass guitar.

Hackings
A hacker under the pseudonym "HackerGiraffe" sent print jobs to around 50,000 vulnerable printers in November, and another hacker under the pseudonym "j3ws3r" did the same to around 80,000 printers in December. Messages were printed out saying "PewDiePie is in trouble and he needs your help to defeat T-Series!" and urging printer users to subscribe to PewDiePie, unsubscribe from T-Series, and fix their printer. HackerGiraffe claimed that he had discovered more than 800,000 vulnerable printers using the search engine Shodan used for finding vulnerable devices. In January 2019, more than 65,000 of Google’s Chromecast streaming dongles were hacked by HackerGiraffe and j3ws3r, displaying a message on smart TVs urging people to subscribe to PewDiePie and adjust their security settings. However, despite positive feedback from some people, one of the hackers anonymously revealed to the BBC that he suffered a breakdown due to the prospect of facing jail time and angry messages urging him to commit suicide. Both hackers are in hiding, but do not regret their decisions due to a lower number of vulnerable printers which they believe is due to their hack. Also in January, dozens of Nest Cameras were compromised by a hacker under the pseudonym "SydeFX" using credential stuffing, who spoke to victims through the cameras, demanding they subscribe to PewDiePie.

Hacking was not limited to hardware. In December 2018, one of the Wall Street Journal's websites was hacked to display a message apologising for articles accusing PewDiePie of anti-Semitism and to tell readers to subscribe to his channel. The hacker j3ws3r also took down T-Series' website with a denial-of-service attack. In February 2019, Bob Buckhorn, the mayor of Tampa, Florida, had his Twitter account hacked to post many malicious tweets one of these being to encourage users to subscribe to PewDiePie. On 22 March 2019, A user on the PewDiePie subreddit developed ransomware by the name PewCrypt that encrypted files on Microsoft Windows machines. The attacker claimed he would release an encryption key when PewDiePie hit the 100 million Subscriber milestone, however, the author claimed that if T-Series claims that goal first, the encryption tool would be deleted permanently.

Other activism
The UK Independence Party announced their support for PewDiePie in a tweet.

On 27 February 2019, Basketball Club Žalgiris based in Kaunas, Lithuania, had cheerleaders performing to "Bitch Lasagna" during a time-out.

Several marches were held in support of PewDiePie. On 27 February 2019, a parade was held in Tallinn, Estonia in support of PewDiePie. Up to several hundreds of people took part in the march, which went through Tallinn's Old Town and other busy areas of the city centre. During the 2019 India–Pakistan standoff, T-Series removed the music of Pakistani pop artists from its channel. In response, there was a march in Pakistan where protesters held signs reading "Unsubscribe T-Series" and expressed support for PewDiePie. On 10 March 2019, a rally was held in Moscow for internet freedom, coordinated by the Libertarian Party of Russia. During the rally protesters played "Bitch Lasagna" and held signs which read "Sub to PewDiePie".

On 12 March 2019, indie game developer Thomas Brush released a video game on Ichi.io based on PewDiePie vs T-Series called Zero Deaths, which takes place in a post-apocalyptic setting where PewDiePie must defend Marzia Bisognin, his fiancée, from fake YouTube subscribers known as "sub bots".

On 29 April 2019, a plane flew over New York City with a banner attached saying “Subscribe to PewDiePie”. More than 21,000 people watched PewDiePie's live stream on DLive showing the plane with its banner fly over Lower Manhatt. During the live stream, PewDiePie said that the event was "a nice little wrap up" to the Subscribe to PewDiePie meme. The flight and banner, which cost more than $4,500, were crowdfunded by PewDiePie's fanbase.