We analyzed the Russian Internet Research Agency’s (IRA) 2015-2017 English-language information operation on Twitter to understand the special role that engagement with outsiders (i.e., non-IRA affiliated accounts) played in their campaign. By analyzing the timing and type of engagement of IRA accounts with non-IRA affiliated accounts, and the characteristics of the latter, we identified a three-phases life cycle of such engagement, which was central to how this IRA network operated. Engagement with external accounts was key to introducing new troll accounts, to increasing their prominence, and, finally, to amplifying the messages these external accounts produced.
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