Positive feedback via likes and awards is central to online governance, yet which attributes of users’ posts elicit rewards—and how these vary across authors and communities—remains unclear. To examine this, we combine quasi-experimental causal inference with predictive modeling on 11M posts from 100 subreddits. We identify linguistic patterns and stylistic attributes causally linked to rewards, controlling for author reputation, timing, and community context. For example, overtly complicated language, tentative style, and toxicity reduce rewards. We use our set of curated features to train models that can detect highly-upvoted posts with high AUC. Our audit of community guidelines highlights a “policy-practice gap”—most rules focus primarily on civility and formatting requirements, with little emphasis on the attributes identified to drive positive feedback. These results inform the design of community guidelines, support interfaces that teach users how to craft desirable contributions, and moderation workflows that emphasize positive reinforcement over purely punitive enforcement.

Social media platform design often incorporates explicit signals of positive feedback. Some moderators provide positive feedback with the goal of positive reinforcement, but are often unsure of their ability to actually influence user behavior. Despite its widespread use and theory touting positive feedback as crucial for user motivation, its effect on recipients is relatively unknown. This paper examines how positive feedback impacts Reddit users and evaluates its differential effects to understand who benefits most from receiving positive feedback. Through a causal inference study of 11M posts across 4 months, we find that users who received positive feedback made more frequent (2% per day) and higher quality (57% higher score; 2% fewer removals per day) posts compared to a set of matched control users. Our findings highlight the need for platforms, communities, and moderators to expand their perspective on moderation and complement punitive approaches with positive reinforcement strategies to foster desirable behavior online.

The sudden popularity communities gain via algorithmically-curated "trending'" or "hot" social media feeds can be beneficial or disruptive. On one hand, increased attention often brings new users and promotes community growth. On the other hand, the unexpected influx of newcomers can burden already overworked moderation teams. To examine the impact of sudden popularity, we studied 6,306 posts that reached Reddit's front page---a feed called r/popular that millions of users browse daily---and the effects of sudden popularity within 1,320 subreddits. We find that on average, r/popular posts have 45 times the comments, 42 times the removed comments, and 70 times the number of newcomers compared to posts from the same community that did not reach r/popular. Additionally, r/popular posts led to a peak 85% median increase in the subreddit's comment rate, and these effects lingered for about 12 hours. Our regression analysis shows that stricter moderation and previous r/popular appearances were associated with shorter and less intense effects on the community. By quantifying the differential effects of sudden popularity, we provide recommendations for moderators to promote stability and community resilience in the face of unexpected disruptions.

The role of a moderator is often characterized as solely punitive, however, moderators have the power to not only execute reactive and punitive actions but also create norms and support the values they want to see within their communities. One way moderators can proactively foster healthy communities is through positive reinforcement, but we do not currently know whether moderators on Reddit enforce their norms by providing positive feedback to desired contributions. To fill this gap in our knowledge, we surveyed 115 Reddit moderators to build two taxonomies: one for the content and behavior that actual moderators want to encourage and another taxonomy of actions moderators take to encourage desirable contributions. We found that prosocial behavior, engaging with other users, and staying within the topic and norms of the subreddit are the most frequent behaviors that moderators want to encourage. We also found that moderators are taking actions to encourage desirable contributions, specifically through built-in Reddit mechanisms (e.g., upvoting), replying to the contribution, and explicitly approving the contribution in the moderation queue. Furthermore, moderators reported taking these actions specifically to reinforce desirable behavior to the original poster and other community members, even though many of the actions are anonymous, so the recipients are unaware that they are receiving feedback from moderators. Importantly, some moderators who do not currently provide feedback do not object to the practice. Instead, they are discouraged by the lack of explicit tools for positive reinforcement and the fact that their fellow moderators are not currently engaging in methods for encouragement. We consider the taxonomy of actions moderators take, the reasons moderators are deterred from providing encouragement, and suggestions from the moderators themselves to discuss implications for designing tools to provide positive feedback.