Collective dynamics of social annotation

Ciro Cattuto (1) , Alain Barrat (2, 1, 3, 4) , Andrea Baldassarri (5) , G. Schehr (6) , Vittorio Loreto (5)

1 Complex Networks Lagrange Laboratory
2 CPT - E5 Physique statistique et systèmes complexes
3 CPT - Centre de Physique Théorique - UMR 6207
4 CPT - Centre de Physique Théorique - UMR 7332
5 Dipartimento di Fisica
6 LPT - Laboratoire de Physique Théorique d'Orsay [Orsay]

The enormous increase of popularity and use of the WWW has led in the recent years to important changes in the ways people communicate. An interesting example of this fact is provided by the now very popular social annotation systems, through which users annotate resources (such as web pages or digital photographs) with text keywords dubbed tags. Understanding the rich emerging structures resulting from the uncoordinated actions of users calls for an interdisciplinary effort. In particular concepts borrowed from statistical physics, such as random walks, and the complex networks framework, can effectively contribute to the mathematical modeling of social annotation systems. Here we show that the process of social annotation can be seen as a collective but uncoordinated exploration of an underlying semantic space, pictured as a graph, through a series of random walks. This modeling framework reproduces several aspects, so far unexplained, of social annotation, among which the peculiar growth of the size of the vocabulary used by the community and its complex network structure that represents an externalization of semantic structures grounded in cognition and typically hard to access.

Domaines: Ordinateur et société [cs.CY]; Physique et Société [physics.soc-ph]; Mécanique statistique [cond-mat.stat-mech]

Ciro Cattuto, Alain Barrat, Andrea Baldassarri, G. Schehr, Vittorio Loreto. Collective dynamics of social annotation. Proceedings of the National Academy of Sciences of the United States of America, 2009, 106, pp.10511. ⟨10.1073/pnas.0901136106⟩. ⟨hal-00361199v2⟩