People on the move are typically interested in information with respect to their proximity. Location-based services in general supply users with information about their proximity typically relying on an infrastructure storing the information and tracking the mobile objects, i.e. users. In this paper we present an approach for spontaneous, i.e. ad hoc, networks inspired by the Usenet. Information is exchanged using a peer-to-peer synchronization mechanism. The information is made available through channels grouping related information. The information propagation is solely based on spontaneously connected devices not requiring any infrastructure. Our prototype implementation shows the technical feasibility of our approach, whereas simulation results show the applicability of information diffusion in outdoor scenarios with a realistic number of nodes, covering a city center.