Date Added: Mar 2011
The spatial structure of large-scale online social networks has been largely unaccessible due to the lack of available and accurate data about people's location. However, with the recent surging popularity of location-based social services, data about the geographic position of users have been available for the first time, together with their online social connections. In this paper the authors present a comprehensive study of the spatial properties of the social networks arising among users of three main popular online location-based services. They observe robust universal features across them: while all networks exhibit about 40% of links below 100 km, the authors further discover strong heterogeneity across users, with different characteristic spatial lengths of interaction across both their social ties and social triads.