Troll Factories: Manufacturing Specialized Disinformation on Twitter.

We document methods employed by Russia's Internet Research Agency to influence the political agenda of the United States from September 9, 2009 to June 21, 2018. We qualitatively and quantitatively analyze Twitter accounts with known IRA affiliation to better understand the form and function of Russian efforts. We identified five handle categories: Right Troll, Left Troll, News Feed, Hashtag Gamer, and Fearmonger. Within each type, accounts were used consistently, but the behavior across types was different, both in terms of "normal" daily behavior and in how they responded to external events. In this sense, the Internet Research Agency's agenda-building effort was "industrial" – mass produced from a system of interchangeable parts, where each class of part fulfilled a specialized function. [ABSTRACT FROM AUTHOR]