In this thesis, Shan Huang explores the causal relationships between products, social influence, and network-embedded human behaviors within the realm of social advertising. The research involves a large-scale randomized field experiment conducted in collaboration with a social networking app, examining the effects of social cues like "likes" in ads on more than 37 million subjects across 71 products. The study investigates the incentives, patterns of contagion, and viral factors affecting social influence in social advertising and product adoption.