Internet memes used to be funny, but somewhere in the mid-2010's, a darker dimension surfaced. This editorial explores this ‘reactionary turn’ in digital culture through a collection of articles and commentaries on ‘the micropolitics of online oppositional subcultures’. In the special theme, these range from commentaries on how misogyny and hate speech exploit platform affordances to articles tracing the growth and spread of arcane memes and anti-vaccine discourse on Reddit and Telegram. While these phenomena might elsewhere be labeled as instances of misinformation, the editorial frames them in terms of ‘reactionary sensemaking’, in which digital subcultures form communities in reaction to a perceived loss of meaning and out of a shared antipathy to ‘mainstream’ culture. Methodologically, the editorial situates these studies in terms of a broader ‘micropolitical’ research tradition that extends from Latour and Deleuze back to Tarde.