Gender-based violence (GBV) is a global epidemic that is powered, in part, by a culture of silence and denial of the seriousness of its repercussions. In this paper, we present one of the first investigations of GBV in social media. Considering Twitter as an open pervasive platform that provides means for open discourse and community engagement, we study user engagement with GBV related posts, and age and gender dynamics of users who post GBV content. We also study the specific language nuances of GBV-related posts. We find evidence for increased engagement with GBV-related tweets in comparison to other non-GBV tweets. Our hashtag-based topical analysis shows that users engage online in commentary and discussion about political, social movement-based, and commonplace GBV incidents. Finally, with the rise of public figures encouraging women to speak up, we observe a unique blended experience of non-anonymous self-reported assault stories and an online community of support around victims of GBV. We discuss the role of social media and online anti-GBV campaigns in enabling an open conversation about GBV topics and how these conversations provide a lens into a socially complex and vulnerable issue like GBV.