Pop-up campaign subreddits and the 2016 misinformation surge researchers found on Reddit

Reddit's role in the 2016 US presidential election was defined by what researcher Richard Mills called 'pop-up political advocacy communities.' His study in AI & Society traced how r/SandersForPresident began growing rapidly in April 2015 and reached 176,000 subscribers by January 2016. The growth was seeded by the candidate himself: when Bernie Sanders announced his candidacy on 30 April 2015, he posted the announcement to r/SandersForPresident rather than the larger r/politics — a choice Mills argued granted the subreddit 'a kind of endorsement,' directing redditors who saw the post atop r/all to a community they could join. Within days the subreddit went from fewer than 100 comments a day to regularly over 1,000. The community became a genuine campaign apparatus; years later, one of its moderators told Business Insider it grew to more than 510,000 subscribers with, by his estimate, 6 million monthly active users, serving as a major fundraising and volunteer-recruitment platform.

Beginning in February 2016, a community of Donald Trump supporters made its presence felt through r/The_Donald. Mills recorded its first post reaching the r/all page on 21 February 2016 — two days earlier the subreddit had 15,000 subscribers; by April it matched r/SandersForPresident's presence on r/all and by May it was dominating the page. His observational data suggested some members may have been bulk-upvoting nearly everything on the subreddit's pages — a pattern consistent with a strategy aimed at pushing as many posts as possible onto site-wide pages — while moderators 'stickied' rising posts to signal what members should vote on. The dominance prompted or hastened the June 2016 change to how r/all selects posts, announced by CEO Steve Huffman, which curtailed but did not eliminate the subreddit's presence; that algorithm fight is covered in detail elsewhere in this archive. Notably, pro-Clinton communities never achieved comparable visibility: r/HillaryClinton had 32,000 subscribers in October 2016 against the pop-up communities' hundreds of thousands.

The misinformation dimension was quantified by data scientist Rishab Nithyanand, whose research at the Data & Society think tank — conducted with Phillipa Gill and Brian Schaffner and examining 12 million posts and 332 million comments across 124 political subreddits — found that visitors to Republican-affiliated subreddits were 600 percent more likely to see links to controversial sources after the start of the Republican primaries, and 1,600 percent more likely after the July 2016 Republican National Convention, than before the campaigns began. More than 80 percent of all posts and comments linking to such sites appeared on Republican-affiliated subreddits. The flagged sources — identified via the OpenSources vetting project — included sites like beforeitsnews.com, which published a story claiming US Marines were blocking a coup against President Trump.

The researchers also found the 'fringe' moving inward: after December 2015, users who frequented forums discussing violence and hatred toward women, minorities and LGBT people increased their posting on Democratic-affiliated subreddits by 200 percent — and on Republican-affiliated subreddits by 6,600 percent. The more such commenters were present, the more offensive political discussions became. Nithyanand wrote that the team used the pattern 'as evidence in our ongoing investigation of a coordinated misinformation campaign targeted at Republican subreddits.'

What made the findings pointed was Reddit's absence from accountability. When angry lawmakers grilled Facebook, Google and Twitter lawyers over election misinformation in late 2017, Reddit — the fifth most popular website in the US, with more than 250 million users — was missing from two days of hearings. On 1 November 2017, the same day the companies' lawyers were in Washington answering questions, Huffman told users in an AMA that he and Reddit's CTO were personally overseeing the situation: 'We take both the integrity of Reddit and the US elections extremely seriously. We're digging deeply. … When we have something to share, we will.' Reddit declined to comment on the record about Nithyanand's research. The separate question of Russian state accounts — the 944 Internet Research Agency accounts Reddit later disclosed — is covered in its own entry.