study the dissemination of dynamic content, such as news and traffic information, over an MSN. In this application, mobile users subscribe to a dynamic-content distribution service offered by their service provider. To improve coverage and increase capacity, it is assumed that users share any content updates they receive with other users they meet. Reference 14 determines how the service provider can allocate its bandwidth optimally to make the content at users as “fresh” as possible. Moreover, there is a condition under which the system with high scalability is specified: even if the total bandwidth dedicated by the service provider remains fixed, the expected content age at each user grows slowly (as log(n)) with the number of users n.