For many cosmopolitan urban Germans and Europeans in Berlin in the late 2000s, social media platforms were a site where gender and class were enacted through articulations of emergent nerd masculinity or hip, ironic femininity. But these platforms, such as Facebook or Pinterest, encoded normative assumptions about masculinity and femininity in their visual and interaction design, excluding women and acceptable femininity as subjects of technological expertise. Sites that presented themselves as neutral spaces for connection and interaction, like Twitter or Facebook, instantiated gendered understandings of technology that rendered public space implicitly masculine, white, and middle class. Visually based sites like Pinterest and Etsy, in contrast, were marked as domains of feminine domesticity, representing not only a shift to visual communication but to visual modes of interaction that structured gender online. Although many young people resisted hegemonic notions of gender, their social media practices stabilized their class status as aspiring urban cosmopolitans. In this article, I consider how gender and class stabilized temporarily through material-semiotic engagements with technology interfaces.