Social Ties and User-Generated Content: Evidence from an Online Social Network
利用瑞士冲浪地点风速变化作为用户发帖倾向的外生变量，检验用户在线内容生成与社会关系是否相互决定，发现网络效应能促进内容生成和关系密度，进而增加网站访问和广告收入。
We exploit changes in wind speeds at surfing locations in Switzerland as a source of variation in users' propensity to post content about their surfing activity on an online social network. We exploit this variation to test whether users' online content-generation activity is codetermined with their social ties. Economically significant effects of this type can produce positive feedback that generates local network effects in content generation. When quantitatively significant, the increased content and tie density arising from the network effect induces more visitation and browsing on the site, which fuels growth by generating advertising revenue. We find evidence consistent with such network effects. This paper was accepted by J. Miguel Villas-Boas, marketing.