The three focal groups have few bots and are widely followed by other accounts on Twitter.

We estimated numbers of bots by testing 2,000 accounts using Botometer [24] (scores >0.8 were deemed bots). The number of followers was the number of unique accounts on the whole of Twitter that had followed at least one account in each group. The number of followers for all three groups combined is 57 million, comparable in size to the 63M who voted for Trump in the election. Figures are given to 2 d.p., K means thousands, and M means millions.