Which functions do social media fill for non-state armed groups in countries with internal armed conflict? Building on conflict data, interviews and media monitoring, we have reviewed the use of social media by Myanmar’s nine most powerful armed groups. The first finding is that they act like states, using social media primarily to communicate with their constituents. Second, they also use social media as a tool of armed struggle, for command and control, intelligence, denunciation of traitors, and attacks against adversaries. Third, social media serves for national and international outreach. Like Myanmar’s national army, the armed groups have combined prudent official pages with an underworld of more reckless profiles and closed groups that often breach Facebook’s official community standards. In February 2019, when Facebook excluded four groups from its platform, they lost much of their ability to reach out and act like states. Yet they kept a capacity to communicate with their constituents through closed groups, individual profiles and sophisticated use of links and shares. Finally, the article affirms that the Facebook company, in the years 2018–2020,took upon itself a role as an arbiter within Myanmar’s internal conflicts, deciding what information was allowed and disallowed.