Does Online Word of Mouth Increase Demand? (And How?) Evidence from a Natural Experiment
利用新浪微博因政治事件被暂时关闭评论的自然实验，研究发现微博评论数量对电视节目收视率有微小但显著的正向影响，且这种影响主要来自节目播出后的评论，而非播出前的评论。
We leverage a temporary block of the Chinese microblogging platform Sina Weibo due to political events to estimate the causal effect of online word-of-mouth content on product demand in the context of TV show viewership. Based on this source of exogenous variation, we estimate an elasticity of TV show ratings (market share in terms of viewership) with respect to the number of relevant comments (comments were disabled during the block) of 0.016. We find that more postshow microblogging activity increases demand, whereas comments posted prior to the show airing do not affect viewership. These patterns are inconsistent with informative or persuasive effects and suggest complementarity between TV consumption and anticipated postshow microblogging activity. Data and the online appendix are available at https://doi.org/10.1287/mksc.2017.1045 .