Regensburg 2007 – wissenschaftliches Programm
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AKSOE: Arbeitskreis Physik sozio-ökonomischer Systeme
AKSOE 10: Social-, Information-, and Production Networks
AKSOE 10.2: Vortrag
Mittwoch, 28. März 2007, 14:00–14:30, H8
Stochastic models for social tagging behavior — •Ciro Cattuto1,2, Vittorio Loreto2, and Luciano Pietronero2 — 1Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Roma, Italy — 2La Sapienza University Physics Department, Roma, Italy
A new paradigm has been quickly gaining ground on the World Wide Web: Collaborative Tagging. In web applications like del.icio.us, Flickr, Connotea, users manage their personal collection of online resources by enriching them with semantically meaningful information in the form of freely chosen tags. Despite the anarchic nature of users' behavior, the global dynamics of these systems leads to a self-organised categorization (folksonomy) of a large and evolving body of information. Here we collect data from a popular online system and select a semantic context by extracting all the resources associated with a given tag. On studying the distribution of tags co-occurring with the selected one, we find a heavy-tailed behavior and observe properties that point to an emergent hierarchy of tags. We introduce a stochastic model embodying two main aspects of collaborative tagging: (i) a multiplicative character related to the exposure of users to each other's activity; (ii) a notion of long-term memory. Remarkably, our model is able to account quantitatively for the measured properties of tag association, providing a clear indication that collaborative tagging is able to recruit the uncoordinated actions of web users to create a coherent and predictable semiotic dynamics at the emergent level.