  The Russian Internet Research Agency's (IRA) online interference campaign in
the 2016 U.S. presidential election represents a turning point in the
trajectory of democratic elections in the digital age. What can we learn about
how the IRA engages U.S. audiences, ahead of the 2020 U.S. presidential
election? We provide the first in-depth analysis of the relationships between
IRA content characteristics and user engagement on Facebook and Instagram
around the 2016 election. We find that content targeting right-wing and
non-Black marginalised groups had the strongest positive association with
engagement on both Facebook and Instagram, in contrast to findings from the IRA
campaign on Twitter and to some previous commentary in the media. Higher
engagement was associated with posting later in the 2015-2017 period and using
less text on both platforms, using negative wording and not including links on
Facebook, and using fewer hashtags on Instagram. The sub-audiences and
sub-issues associated with most engagement differed across the platforms.
