This study examines contemporary gatekeeping as it intersects with the evolving technological affordances of social media platforms and the ongoing negotiation of professionalized journalistic norms and routines in contentious politics. Beginning with a corpus of just over 4.2 million Tweets about the racially charged Ferguson, Missouri protests, a series of network analyses were applied to track shifts over time and to identify influential actors in this communicative space. These models informed further analyses that indicated legacy news organizations and affiliated journalists were least present and only marginally engaged in covering these events, and that other users on Twitter emerged as far more prominent gatekeepers. Methodological considerations and implications about the importance of dialogic and reciprocal activities for journalism are discussed.