Too Long, Didn't Read? The Impact of Length Limits on Microblogging Engagement.

This article investigates the impact of extending length limits—the maximum number of characters allowed per post—on user engagement in social media, focusing on Weibo, a leading Chinese microblogging platform. Using a natural experiment from Weibo's phased rollout of increasing its character limit from 140 to 2,000 characters, the study finds that longer length limits significantly increase the number of daily posts (by about 1.92%) and the number of likes per post (by about 6.73%), indicating enhanced user activity and audience engagement. However, this increase in posting frequency is primarily driven by already active users, with little change among less active users, suggesting that extending length limits may concentrate content generation within a vocal minority and reduce the visibility of the silent majority. These findings are supported by a randomized experiment on Twitter and various robustness checks, highlighting important considerations for platform managers regarding the trade-offs of length limit policies on user participation and content diversity.