Under the practice of “digital co-op”, manufacturers subsidize the online advertising expenditures of retailers that they sell their products through, even though retailers typically compete with manufacturers in the advertising market and appropriate a share of the manufacturers' channel...

E-commerce platforms, such as Amazon, Alibaba and Flipkart, that match sellers and consumers at an unprecedented scale, operate their internal search engines to help buyers find relevant products from a large number of sellers, and also allow sellers to advertise to consumers for positions in...