What is in a like?. Preference aggregation on the social web

The Social Web is dominated by rating systems such as the ones of Facebook (only ""Like""), YouTube (both ""Like"" and ""Dislike""), or the Amazon product review 5-star rating. All these systems try to answer on How should a social application pool the preferences of different agents so as to best reflect the wishes of the population as a whole? The main framework is the theory of social choice (Arrow, Social choice and individual values, Wiley, New York, 1963; Fishburn, The theory of social choice, Princeton University Press, Princeton, 1973) i.e., agents have preferences, and do not try to camouflage them in order to manipulate the outcome to their personal advantage (moreover, manipulation is quite difficult when interactions take place at the Web scale). Our approach uses a combination between the Like/Dislike system and a 5-star satisfaction system to achieve local preference ranks and a global partial ranking on the outcomes set. Moreover, the actual data collection can support other preference learning techniques such as the ones introduced by Baier and Gaul (J. Econ. 89:365-392, 1999), Cohen et al. (J. Artif. Intel. Res. 10:213-270, 1999), Fürnkranz and Hüllermeier (Künstliche Intelligenz 19(1):60-61, 2005), and Hüllermeier et al. (Artif. Intel. 172(16-17):1897-1916, 2008).