  The proliferation of harmful content shared online poses a threat to online
information integrity and the integrity of discussion across platforms. Despite
various moderation interventions adopted by social media platforms, researchers
and policymakers are calling for holistic solutions. This study explores how a
target platform could leverage content that has been deemed harmful on a source
platform by investigating the behavior and characteristics of Twitter users
responsible for sharing moderated YouTube videos. Using a large-scale dataset
of 600M tweets related to the 2020 U.S. election, we find that moderated
Youtube videos are extensively shared on Twitter and that users who share these
videos also endorse extreme and conspiratorial ideologies. A fraction of these
users are eventually suspended by Twitter, but they do not appear to be
involved in state-backed information operations. The findings of this study
highlight the complex and interconnected nature of harmful cross-platform
information diffusion, raising the need for cross-platform moderation
strategies.
