This article considers how the social-news and community site Reddit.com has become a hub for anti-feminist activism. Examining two recent cases of what are defined as "toxic technocultures" (#Gamergate and The Fappening), this work describes how Reddit’s design, algorithm, and platform politics implicitly support these kinds of cultures. In particular, this piece focuses on the ways in which Reddit’s karma point system, aggregation of material across subreddits, ease of subreddit and user account creation, governance structure, and policies around offensive content serve to provide fertile ground for anti-feminist and misogynistic activism. The ways in which these events and communities reflect certain problematic aspects of geek masculinity are also considered. This research is informed by the results of a long-term participant-observation and ethnographic study into Reddit’s culture and community and is grounded in actor-network theory.