Advanced Service Schemes for a Self-Interested Information Platform (Extended Abstract) Chen Hajaj Computer Science department Bar-Ilan University, Ramat-Gan, Israel 52900 hajajch@cs.biu.ac.il David Sarne Computer Science department Bar-Ilan University, Ramat-Gan, Israel 52900 sarned@cs.biu.ac.il Lea Perets Computer Science department Bar-Ilan University, Ramat-Gan, Israel 52900 lea.perets@gmail.com ABSTRACT This paper deals with platforms that bring together agents and opportunities of the type in which they are interested (e.g., eCommerce platforms, used car bulletins and dating web sites). It shows that the platform can benefit from not necessarily listing all of the opportunities that it can po- tentially list, even if there is no marginal cost for listing any additional opportunity. Two important implications of this result are discussed and demonstrated. The first is that the platform should take into account the option to dis- close different subsets of opportunities, whenever setting its expected-profit-maximizing service fee. The second is that from the platform’s users point of view, it might turn out to be more beneficial to pay for the platform’s service rather than get it for free (e.g., when the service is sponsored by ads), as the costly case is characterized by more favorable listings. Categories and Subject Descriptors I.2.11 [Artificial Intelligence]: Distributed Artificial In- telligence—Multiagent Systems Keywords E-commerce; Multi agents systems; Selective disclosure; Ser- vice schemes; Stackleberg game. 1. INTRODUCTION In many two-sided multi-agent markets the number of opportunities potentially available to agents is substantial, however the agent needs to spend time and resources in lo- cating these opportunities [2]. For example, a buyer who is interested in buying a specific product over the internet can potentially find this product in literally hundreds of online stores, most of which are unknown to her. This plethora of opportunities has been a catalyst for the emergence of platforms that serve as mediators and are used primarily as a point of contact for users and opportunities, saving users the need to invest their valuable resources in service or op- portunity discovery [3]. Appears in: Alessio Lomuscio, Paul Scerri, Ana Bazzan, and Michael Huhns (eds.), Proceedings of the 13th Inter- national Conference on Autonomous Agents and Multiagent Systems (AAMAS 2014), May 5-9, 2014, Paris, France. Copyright c  2014, International Foundation for Autonomous Agents and Multiagent Systems (www.ifaamas.org). All rights reserved. One of the most prominent questions in platforms research is how a platform should price its (information providing) services. Being a self-interested agent, the platform seeks to maximize its profit, taking into consideration its own information providing costs and the payments it receives. The payments can be received from any of the sides using the market (e.g., buyers, sellers), taking over some of their surplus from using the platform. Alternatively, payments can be received from external entities that may benefit from the activity taking place in the market (e.g., advertisers or repositories willing to buy user information collected by the platform). Prior work which considered the service-pricing question was taking the set of information listed by the plat- form to be given. In real-life, however, the platform is not limited to price-setting only but can control what informa- tion will be included in its listings[1]. In this paper we analyze richer service-terms-setting strate- gies for the platform, ones that do not take the set of op- portunities to be presented to be fixed, but rather allow the platform to control what subset of these will be pre- sented. For example, in cases where the platform’s profit is fully based on advertisements scattered throughout the different pages, the platform can potentially benefit from omitting some of the more attractive opportunities from its listings. One important finding, of an existential nature, that results from the richer service-terms-setting strategies is that from the users’ point of view, the free use of platforms, e.g., those that are sponsored by ads, is not necessarily the preferred choice. The preference of the “costly” alternative by the users is explained in our case by a more favorable listing. Furthermore, we demonstrate that for some settings the costly option is the dominant one both for the platform and for all users individually. 2. MODEL The model builds on a standard platform-based one-sided search model of the kind commonly used in prior litera- ture [4]. For exposition purposes, we adopt the procurement application domain terminology. The procurement setting considers a platform such as alibaba.com, made-in-china. com, and gobizkorea.com that brings together procurement agents (denoted“buyers”onwards) and sellers (typically small businesses worldwide). Buyers are assumed to be self-interested fully-rational agents. In order to successfully complete their task, buyers need to locate sellers that sell the product in which they are inter-