Collective audience gatekeeping dalam produksi berita di media online tribunnews.com : studi pada Pilkada DKI Jakarta 2017 pada masa kampanye putaran kedua, 1-18 April 2017 = Collective audience gatekeeping in the production of news in the online news portal tribunnews com : study in the period of the second round of the gubernatorial election campaign 1-18 April 2017