We study resale platforms, an emerging type of online marketplaces in developing countries. Resale platforms are designed for individuals (resellers) to sell products to others as opposed to buying for themselves, enabling them to supplement their income by earning a margin on the transactions they generate. One challenge these platforms face is that competition among resellers may emerge as more of them join the platform, as their social circles increasingly overlap.

We explore the welfare implications of data tracking technologies that enable firms to collect consumer data and potentially use it for price discrimination. The model we develop centers around two features: first, competition between firms and, second, consumers' level of sophistication. Our baseline environment features a firm that can collect information about the consumers it transacts with in a duopoly market, which it can then use in a second monopoly market. We characterize and compare the equilibrium outcomes in three settings of interest: (i) an economy with myopic consumers, who, when making purchase decisions, do not internalize the fact that firms have the ability to track their behavior and use this information in future transactions, (ii) an economy with forward-looking consumers, who take into account the implications of data tracking when determining their actions, and (iii) an economy where no data tracking technologies are used either due to technological or regulatory constraints.