Social media allows individuals and businesses to contribute contents for public viewing. However, little is known about the underlying incentives that why content providers derive utilities from such activities. In this study, we build a dynamic structural model to recover the utility function for content providers. Our model distinguishes short-term payoffs based on ad revenue sharing from long-term payoffs driven by content providers' reputation. The model was estimated using a panel data of 914 top 1000 video providers on YouTube from Jun 7th, 2010, to Aug 7th, 2011 since top providers are more likely to be encouraged by these incentives. Our results show that video providers value incremental subscribers as much as incremental video views. We also find that top providers' reputation is influenced more by accumulative subscribers than by accumulative video views.