Too Long, Didn’t Read? The Impact of Length Limits on Microblogging Engagement
利用中国微博平台逐步放宽字数限制的自然实验，研究发现放宽限制增加了活跃用户的发帖量和每帖点赞数，但可能加剧内容生产向少数活跃用户集中。
Social media platforms aggressively compete for the participants who create content on their sites. In this study, we delve into one tactic of this competition that has become increasingly popular but received limited scholarly attention—the extension of length limits (i.e., the maximum number of characters in a post)—and how it affects both the production and consumption of social media posts. We investigate these questions by exploiting a natural experiment, the phased rollout of length limit extensions on a leading Chinese microblog platform. Findings suggest that extending length limits significantly increased the number of daily posts of individual users. However, and strikingly, only already active users appear to post more after the extension with little observed change from less active users. Further, results show that extending length limits increases the number of likes each post receives, indicating that extensions improve content quality and may increase engagement in the long term. This suggests that, by permitting longer posts, social media platforms can facilitate engagement from both the post generators and audiences (at least in terms of likes). However, findings also suggest that extending length limits risks further concentrating content generation from the vocal minority, thereby making the silent majority less visible on the platforms. This paper was accepted by Anindya Ghose, information systems. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2021.03629 .