insights into understanding and designing many emerging and envisioned classes of applications.

Motivation
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Many emerging networks are formed endogenously by self-interested agents, who take information sharing and production actions. Examples of such networks are: dynamic spectrum management by wireless users [@ref1], social networks overlaid on technological networks [@ref4] [@ref5], device-to-device (D2D) communications, vehicular networks [@ref7], Internet-of-Things (IoT) [@ref72], and smart sensor networks [@ref73]. In many of these networks, users connect to each other in order to exchange and gather information. For instance, secondary users exchange information about spectrum occupancy in cognitive radio networks [@ref8] [@ref9], autonomous rescue robots exchange environmental sensory information [@ref72] [@ref10], D2D users engage in short range communications in order to exchange data content of Social Networks Services (SNSs) [@refnew1], and self-interested users take capacity allocation decisions for multicast streaming over networks [@refnew2]. Users in such networks possess two key features: they are [*opportunistic*]{}, in the sense that they exploit their opportunistic encounter with other mobile users to establish short-range communication links with them, and they are [*cognitive*]{}, in the sense that they need to reason about establishing costly communication links with others given the value of information they can get via these links. Information in 