  Today mobile users are intensively interconnected thanks to the emerging
mobile social networks, where they share location-based information with each
other when traveling on different routes and visit different areas of the city.
In our model the information collected is aggregated over all users' trips and
made publicly available as a public good. Due to information overlap, the total
useful content amount increases with the diversity in path choices made by the
users, and it is crucial to motivate selfish users to choose different paths
despite the potentially higher costs associated with their trips. In this paper
we combine the benefits from social information sharing with the fundamental
routing problem where a unit mass of non-atomic selfish users decide their
trips in a non-cooperative game by choosing between a high-cost and a low-cost
path. To remedy the inefficient low-content equilibrium where all users choose
to explore a single path (the low-cost path), we propose and analyse two new
incentive mechanisms that can be used by the social network application, one
based on side payments and the other on restricting access to content for users
that choose the low cost path. We also obtain interesting price of anarchy
results that show some fundamental tradeoffs between achieving path diversity
and maintaining greater user participation, motivating a combined mechanism to
further increase the social welfare. Our model extends classical dynamic
routing in the case of externalities caused from traffic on different paths of
the network.
