Lost in the Crowd: How Group Size and Content Moderation Shape User Engagement in Live Streaming

Despite the focus of the digital content literature on asynchronous platforms (e.g., Reddit, Wikipedia, Yelp), synchronous content platforms like live streaming (e.g., Twitch, Youtube Live) have become increasingly popular for enabling real-time user engagement at scale. These platforms involve engaging a sizable user base, facilitating their interactions within a contemporaneous environment. As group size increases, real-time interactivity scales rapidly, making the engagement interface fast-paced and erratic. Consequently, livestreaming channels often use moderators to address the challenge. Although the existing literature finds that the audience’s group size has a positive effect on user engagement on asynchronous platforms, how group size affects synchronous interactions, particularly with the presence of bot and human moderators, is unclear. In this work, we leverage exogenous increases in live streaming viewers (from the Raid function in Twitch) to empirically examine the impact of group size on commenters’ engagement in real time. Furthermore, we delve into the role of moderators and their influence on this nuanced dynamic. Leveraging difference-in-differences as the econometric identification strategy, we analyze panel data constructed with chat histories of 7,074 playbacks on Twitch. The results suggest that (a) existing commenters tend to engage less after the increases in group size; (b) the negative engagement effect is the product of mediation effects by way of the increased topic incoherence and emotional polarity of comment (herein referred to as “comment polarity”) that decreases engagement; and (c) live streaming channels adopting bot or human moderators can better curb the negative effect, such that bot moderators are effective in decreasing the escalation of incoherence, particularly when the incoming Raider group is large, although human moderators better limit surges in comment polarity, particularly when the incoming Raider group is small. The findings in this paper indicate a congestion effect, a negative externality of increasing group size on commenter engagement in synchronous content platforms, further revealing a nuanced relationship among group size, topic incoherence, comment polarity, and user engagement. Our research further suggests the beneficial role of content moderators, which provides implications for online platform operators and policymakers.