Reading the Source Code of Social Ties ∗ Luca Maria Aiello Rossano Schifanella Bogdan State Yahoo Labs University of Torino Stanford University Barcelona, Spain Torino, Italy Palo Alto, CA, USA
[email protected] [email protected] [email protected] ABSTRACT are usually treated as a priori entities, immediately available to the Though online social network research has exploded during the researcher from the graph of online-mediated interactions such as past years, not much thought has been given to the exploration of emailing, following on Twitter, or friending on Facebook. The so- the nature of social links. Online interactions have been interpreted cial tie is indeed a powerful abstraction that has allowed researchers as indicative of one social process or another (e.g., status exchange to build rigorous models to describe the evolution of social net- or trust), often with little systematic justification regarding the re- works and the dynamics of information exchange [23]. lation between observed data and theoretical concept. Our research Even though previous research on social networks has explored aims to breach this gap in computational social science by propos- the intensity of social links, as well as their polarity [22, 34], there ing an unsupervised, parameter-free method to discover, with high is still much to investigate about the nature of the social interac- accuracy, the fundamental domains of interaction occurring in so- tions implied by social ties. One way to overcome this limitation cial networks. By applying this method on two online datasets dif- is to look into the content of social links, the messages exchanged ferent by scope and type of interaction (aNobii and Flickr) we ob- between actors.