Human-Computer Interaction Institute
School of Computer Science, Carnegie Mellon University


Supporting Volunteer Moderation Practices in Online Communities

Joseph Seering

September 2020

Ph.D. Thesis


Keywords: Content moderation, platforms, social computing, computer-supported cooperative work, social media, volunteer moderators, cooperative responsibility, Twitch, Reddit, Facebook, AI-mediated communication, social identity theory, rebukes, interpersonal moderation, governance, communities, online communities, selfgovernance, self-moderation, literature review, platforms and policies, commercial content moderation, humancentered design, metaphors, computational social science, thematic analysis, interviews, digital labor, hate speech, harassment, social networks.

In this dissertation, I explore multiple levels of the content moderation ecosystem with a focus on platforms that rely extensively on volunteer user labor. These platforms, like Reddit, Twitch, and Facebook Groups, expect users to moderate their own communities, but reserve the right to intervene when communities or content therein violates sitewide standards for behavior. This thesis contains three parts. I begin with a high-level exploration of how platforms do and do not engage with volunteer community moderators. I build on the framework of cooperative responsibility to analyze the different ways platforms and users have found common ground on values, roles, and spaces for deliberation. Next, I focus in depth on the philosophies and mental models of the volunteer moderators, analyzing the metaphors they used both explicitly and implicitly to describe the work they do. Finally, I dive into the specifics of interpersonal language use in moderation, looking at how both interpersonal "rebukes" impact subsequent comment threads on Reddit and how changes of rules in communities on Reddit impact subsequent behavior of community members. For each of these linguistic pieces, I present results from a related experiment, in which I used a custom-built comment forum to test the impact of simulated "rebukes" and rules. This work shows the nuance of several core processes in user-driven moderation, ranging from the very high level organizational interactions to very low level linguistic features of user comments, and I argue that more attention toward understanding these processes in Computer-Supported Cooperative Work and related fields is needed.

175 pages

Thesis Committee:
Geoff Kaufmann (Chair)
Jason Hong
Robert Kraut
Michael Bernstein (Stanford University)

Jodi Forlizzi, Head, Human-Computer Interaction Institute
Martial Hebert, Dean, School of Computer Science

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