  Much of the research in online moderation focuses on punitive actions.
However, emerging research has shown that positive reinforcement is effective
at encouraging desirable behavior on online platforms. We extend this research
by studying the "creator heart" feature on YouTube, quantifying their primary
effects on comments that receive hearts and on videos where hearts have been
given. We find that creator hearts increased the visibility of comments, and
increased the amount of positive engagement they received from other users. We
also find that the presence of a creator hearted comment soon after a video is
published can incentivize viewers to comment, increasing the total engagement
with the video over time. We discuss the potential for creators to use hearts
to shape behavior in their communities by highlighting, rewarding, and
incentivizing desirable behaviors from users. We discuss avenues for extending
our study to understanding positive signals from moderators on other platforms.
