"Community Guidelines Make This the Best Party on the Internet": an In-Depth Study of Online Platforms' Content Moderation Policies.

Moderating user-generated content on online platforms is crucial forbalancing user safety and freedom of speech. Particularly in the United States,platforms are not subject to legal constraints prescribing permissible content.Each platform has thus developed bespoke content moderation policies, but thereis little work towards a comparative understanding of these policies acrossplatforms and topics. This paper presents the first systematic study of thesepolicies from the 43 largest online platforms hosting user-generated content,focusing on policies around copyright infringement, harmful speech, andmisleading content. We build a custom web-scraper to obtain policy text anddevelop a unified annotation scheme to analyze the text for the presence ofcritical components. We find significant structural and compositional variationin policies across topics and platforms, with some variation attributable todisparate legal groundings. We lay the groundwork for future studies ofever-evolving content moderation policies and their impact on users.