Holocaust denial has long been one of the most insidious conspiracy theories targeting Jewish communities, with its extremist proponents drawn from across the ideological spectrum, from extreme right-wing to hard left to Islamist. Research has shown that digital platforms have only served to amplify and mainstream this warped strain of thinking in recent years.

By analysing the term ‘holohoax’, which is commonly used by Holocaust deniers, this paper examines the extent to which Holocaust denial content is readily accessible across Facebook, Twitter, Reddit and YouTube. Although this study does not set out to provide a comprehensive overview of the phenomenon, it reveals important insights about how Facebook and Twitter provide a home to an established and active community of Holocaust deniers. While Holocaust denial is present on Reddit, our research suggests that such activity has been reduced through a combination of moderation efforts and pushback from other users. This paper also demonstrates how appropriately applied content moderation policies can be effective in denying dangerous conspiracy theorists a public platform by examining how Holocaust denial content has decreased significantly in the past year on YouTube.