Mainstream logic supports the idea that platforms bring large benefits to firms, especially smaller ones, by opening up access to a broader set of consumers and making firms' products easier to find. However, this argument mostly applies to transaction platforms that match consumer preferences...

We consider an infinite-horizon differential game played by two direct marketers. Each player controls the number of emails sent to potential customers at each moment in time. There is a cost associated to the messages sent, as well as a potential reward. The latter is assumed to depend on the...