Positive-Sum Impact of Multistakeholder Recommender Systems for Urban Tourism Promotion and User Utility

When a multistakeholder recommender system (MRS) is designed to produce sustainable urban tourism promotion, two conflicting goals are of practical interest: (i) to cut down the number of visitors at popular sites and (ii) to satisfy tourists’ preferences, often biased towards popular sites. By modelling the tourists’ limited knowledge of the visited city — an important but often overlooked detail — we simulate interactions between tourists and an MRS that jointly optimises tourist’s utility and promotes less popular sites. Experiments based on data logs collected in three tourist cities reveal that such an MRS can lift tourist’s utility and at the same time reduce the number of visitors at popular sites, manifesting a so-called positive-sum impact. However, a delicate balance is crucial; under- or over-promotion of unpopular sites in the recommendation lists can be adverse to both destination and tourist’s utility.