Does Length Impact Engagement? Length Limits of Posts and Microblogging Behavior

Managers of social media platforms aggressively compete for users to stimulate user generated content on their sites. In this study, we delve into one tactic of this competition which has become increasingly popular, but has received limited attention, the extension of character limits. Despite its popularity, the impact of changing these limits on user engagement and behavior is unclear. On the one hand, increasing limits might yield more low quality and rambling posts, thereby alienating the users who favor microblogs for their streamlined and efficient content. On the other hand, increasing limits might give users the freedom they need to more effectively communicate ideas. We delve into this tension by exploiting a natural experiment, the phased rollout of length limit extensions on the Chinese microblog, Weibo. As expected, findings from more than 7,000 users suggest that extending length limits increases the average length of posts. However, results also indicate that the magnitude of the effect is infinitesimal (only 2 characters). Further, results indicate that extending length limits significantly increases user engagement by enticing users into posting more actively. Finally, it appears that accessing the platform through tethered or mobile connection strongly moderates these effects; inasmuch as the observed changes to post length and volumes are only observed for PC users (versus mobile-only users). This suggests a potential risk in extending length limits by shifting the platform away from mobile-only users.