  An increasing number of mobile applications (abbrev. apps), like Pokemon Go
and Snapchat, reward the users who physically visit some locations tagged as
POIs (places-of-interest) by the apps. We study the novel POI-based
collaboration between apps and venues (e.g., restaurants). On the one hand, an
app charges a venue and tags the venue as a POI. The POI tag motivates users to
visit the venue, which potentially increases the venue's sales. On the other
hand, the venue can invest in the app-related infrastructure, which enables
more users to use the app and further benefits the app's business. The apps'
existing POI tariffs cannot fully incentivize the venue's infrastructure
investment, and hence cannot lead to the most effective app-venue
collaboration. We design an optimal two-part tariff, which charges the venue
for becoming a POI, and subsidizes the venue every time a user interacts with
the POI. The subsidy design efficiently incentivizes the venue's infrastructure
investment, and we prove that our tariff achieves the highest app's revenue
among a general class of tariffs. Furthermore, we derive some counter-intuitive
guidelines for the POI-based collaboration. For example, a bandwidth-consuming
app should collaborate with a low-quality venue (users have low utilities when
consuming the venue's products).
