This article explores how the notion of “extreme speech” can advocate a context-specific, practice-oriented approach to alt-right digital culture while also foregrounding its imbrication in larger histories of racial formation. Designating the popular White-nationalist hashtag #whitegenocide as an alt-right structure of feeling, it uses a data-critical discourse on “digital traces” to support a form of social media ethnography that traces affective communication practices online. Bringing this framework to the analysis of top #whitegenocide retweets, it elaborates the functioning of alt-right affective economies of transgression, which, driven by reactionary irony and a sense of race-based threat, contribute to shaping civil discourse and defining Whiteness in digital spaces. Finally, it investigates how the locative and corporal traces left by individual #whitegenocide retweeters both shape and are shaped by larger affective economies of transgression.