Online platforms allow gathering a vast amount of information about consumers’ preferences and characteristics. This information can (i) be used by the platform when selling directly to consumers, and (ii) be sold to those firms adopting the platform for their transactions with consumers. Considering both perspectives, we discuss how finer information at the disposal of the platform and/or the firms impacts the profits and the consumer surplus. We consider both a scenario with a single platform or a single firm (monopoly), and a scenario with several platforms or several firms (oligopoly).