  It is a widely accepted fact that state-sponsored Twitter accounts operated
during the 2016 US presidential election, spreading millions of tweets with
misinformation and inflammatory political content. Whether these social media
campaigns of the so-called "troll" accounts were able to manipulate public
opinion is still in question. Here, we quantify the influence of troll accounts
on Twitter by analyzing 152.5 million tweets (by 9.9 million users) from that
period. The data contain original tweets from 822 troll accounts identified as
such by Twitter itself. We construct and analyse a very large interaction graph
of 9.3 million nodes and 169.9 million edges using graph analysis techniques,
along with a game-theoretic centrality measure. Then, we quantify the influence
of all Twitter accounts on the overall information exchange as is defined by
the retweet cascades. We provide a global influence ranking of all Twitter
accounts and we find that one troll account appears in the top-100 and four in
the top-1000. This combined with other findings presented in this paper
constitute evidence that the driving force of virality and influence in the
network came from regular users - users who have not been classified as trolls
by Twitter. On the other hand, we find that on average, troll accounts were
tens of times more influential than regular users were. Moreover, 23% and 22%
of regular accounts in the top-100 and top-1000 respectively, have now been
suspended by Twitter. This raises questions about their authenticity and
practices during the 2016 US presidential election.
