A large-scale characterization of online incitements to harassment across platforms

Attack strategies used by online harassers have evolved over time to inflict increasing harm to their targets. In addition to scaling harassment through incitement and coordination, online communities that commonly engage in harassment are likely a source of "innovation" for harassment attack strategies. We use the incitements or calls to harassment posted by members of these communities as a lens through which to holistically measure and understand this ecosystem. We create a filtering pipeline to discover 14,679 incitements to harassment within four large-scale data sets of messages and posts that span multiple platforms. Our approach studies the coordination itself, detecting inciting language, rather than individual attack types, to understand a broad range of harassment strategies. In particular, this approach allows us to create a taxonomy of attack strategies. We use this taxonomy to categorize the preferred approaches of coordinated attackers and the proportion of incitements for various types of harassment on different platforms. We find that over 50% of the incitements to harassment included calls to report the target to authorities or their respective platforms. Finally, we provide suggestions for actions and future research that could be performed by researchers, platforms, authorities, and anti-harassment groups.