@inproceedings{1150476,
  abstract = {In this paper, we consider the evolution of structure within large online social networks. We present a series of measurements of two such networks, together comprising in excess of five million people and ten million friendship links, annotated with metadata capturing the time of every event in the life of the network. Our measurements expose a surprising segmentation of these networks into three regions: singletons who do not participate in the network; isolated communities which overwhelmingly display star structure; and a giant component anchored by a well-connected core region which persists even in the absence of stars.We present a simple model of network growth which captures these aspects of component structure. The model follows our experimental results, characterizing users as either passive members of the network; inviters who encourage offline friends and acquaintances to migrate online; and linkers who fully participate in the social evolution of the network.},
  added-at = {2008-04-05T14:58:45.000+0200},
  address = {New York, NY, USA},
  author = {Kumar, Ravi and Novak, Jasmine and Tomkins, Andrew},
  biburl = {http://www.bibsonomy.org/bibtex/203874e666c56f22bce1b7db254420d77/andreab},
  booktitle = {KDD '06: Proceedings of the 12th ACM SIGKDD international conference on Knowledge discovery and data mining},
  description = {Structure and evolution of online social networks},
  doi = {http://doi.acm.org/10.1145/1150402.1150476},
  interhash = {d3729a29d377e03b31c80bcc58843681},
  intrahash = {03874e666c56f22bce1b7db254420d77},
  isbn = {1-59593-339-5},
  keywords = {2006 analysis flickr imported models network social structure yahoo},
  location = {Philadelphia, PA, USA},
  pages = {611--617},
  publisher = {ACM},
  timestamp = {2008-04-05T14:58:45.000+0200},
  title = {Structure and evolution of online social networks},
  url = {http://portal.acm.org/citation.cfm?id=1150476#},
  year = 2006
}

@misc{liu-2006,
  added-at = {2007-04-28T16:14:22.000+0200},
  author = {Liu, Chengshi},
  biburl = {http://www.bibsonomy.org/bibtex/24614f82692f88054ac74bd0c430908a1/andreab},
  description = {[cs/0611038] Nonsymmetric entropy I: basic concepts and results},
  interhash = {d5169401439c5851c41443d9f0a26f05},
  intrahash = {4614f82692f88054ac74bd0c430908a1},
  keywords = {2006 entropy imported liu mandelbrot tagora zipf},
  timestamp = {2007-04-28T16:14:22.000+0200},
  title = {Nonsymmetric entropy I: basic concepts and results},
  url = {http://www.citebase.org/abstract?id=oai:arXiv.org:cs/0611038},
  year = 2006
}

@misc{liu-2006,
  added-at = {2007-04-28T16:11:21.000+0200},
  author = {Liu, Chengshi},
  biburl = {http://www.bibsonomy.org/bibtex/239bfee23816413547c23b700f2ccb0a1/andreab},
  description = {[cond-mat/0609344] Maximal nonsymmetric entropy leads naturally to Zipf's law},
  interhash = {4ac97b0d65316ae8799b2274533a07c6},
  intrahash = {39bfee23816413547c23b700f2ccb0a1},
  keywords = {2006 d4.1 distribution frequency imported mandelbrot tagora word zipf},
  timestamp = {2007-04-28T16:11:21.000+0200},
  title = {Maximal nonsymmetric entropy leads naturally to Zipf's law},
  url = {http://www.citebase.org/abstract?id=oai:arXiv.org:cond-mat/0609344},
  year = 2006
}

@article{pnas_tagging,
  abstract = {Collaborative tagging has been quickly gaining ground because of its ability to recruit the activity of web users into effectively organizing and sharing vast amounts of information. Here we collect data from a popular system and investigate the statistical properties of tag co-occurrence. We introduce a stochastic model of user behavior embodying two main aspects of collaborative tagging: (i) a frequency-bias mechanism related to the idea that users are exposed to each other's tagging activity; (ii) a notion of memory - or aging of resources - in the form of a heavy-tailed access to the past state of the system. Remarkably, our simple modeling is able to account quantitatively for the observed experimental features, with a surprisingly high accuracy. This points in the direction of a universal behavior of users, who - despite the complexity of their own cognitive processes and the uncoordinated and selfish nature of their tagging activity - appear to follow simple activity patterns.},
  added-at = {2007-04-11T19:19:12.000+0200},
  address = {http://xxx.lanl.gov/abs/cs.CY/0605015},
  author = {Cattuto, Ciro and Loreto, Vittorio and Pietronero, Luciano},
  biburl = {http://www.bibsonomy.org/bibtex/2ceb9c88723801129a13ff1f98fa463af/andreab},
  interhash = {189402152f540f931a0eea5b8538411f},
  intrahash = {ceb9c88723801129a13ff1f98fa463af},
  journal = {Proceedings of the National Academy of Sciences
United States of America},
  keywords = {2006 cattuto collaborative d4.1 del.icio.us delicious dynamics folksonomy loreto semiotic semioticdynamic tagging tagora yule yulesimon},
  pages = 1461,
  timestamp = {2007-04-11T19:19:12.000+0200},
  title = {Semiotic dynamics and collaborative tagging},
  url = {http://xxx.lanl.gov/abs/cs.CY/0605015},
  volume = 104,
  year = 2007
}

@article{cls_yulesimon,
  abstract = {The Yule-Simon model has been used as a tool to describe the growth of diverse systems, acquiring a paradigmatic character in many fields of research. Here we study a modified Yule-Simon model that takes into account the full history of the system by means of a hyperbolic memory kernel. We show how the memory kernel changes the properties of preferential attachment and provide an approximate analytical solution for the frequency distribution density as well as for the frequency-rank distribution.},
  added-at = {2007-04-11T19:16:19.000+0200},
  author = {Cattuto, Ciro and Loreto, Vittorio and Servedio, Vito D.P.},
  biburl = {http://www.bibsonomy.org/bibtex/2d9fd1ea1b4a9ffdaf68332409cf90b6e/andreab},
  interhash = {e1dbe404fff4f827f443889685ce83f1},
  intrahash = {d9fd1ea1b4a9ffdaf68332409cf90b6e},
  journal = {Europhysics Letters},
  keywords = {2006 Simon Yule analytic cattuto d4.1 folksonomy loreto memory model servedio study tagora yulesimon},
  number = 2,
  pages = {208-214},
  timestamp = {2007-04-11T19:16:19.000+0200},
  title = {A Yule-Simon process with memory},
  volume = 76,
  year = 2006
}

@inproceedings{1180904,
  abstract = {A tagging community's vocabulary of tags forms the basis for social navigation and shared expression. We present a user-centric model of vocabulary evolution in tagging communities based on community in uence and personal tendency. We evaluate our model in an emergent tagging system by introducing tagging features into the MovieLens recommender system. We explore four tag selection algorithms for displaying tags applied by other community members. We analyze the algorithms  e},
  added-at = {2007-04-10T15:40:05.000+0200},
  address = {New York, NY, USA},
  author = {Sen, Shilad and Lam, Shyong K. and Rashid, Al Mamunur and Cosley, Dan and Frankowski, Dan and Osterhouse, Jeremy and Harper, F. Maxwell and Riedl, John},
  biburl = {http://www.bibsonomy.org/bibtex/2582641c05e7a0b9396945a951822c83f/andreab},
  booktitle = {CSCW '06: Proceedings of the 2006 20th anniversary conference on Computer supported cooperative work},
  description = {tagging communities vocabulary evolution},
  doi = {http://doi.acm.org/10.1145/1180875.1180904},
  interhash = {96b20bffcbc91e528461529935524b90},
  intrahash = {582641c05e7a0b9396945a951822c83f},
  isbn = {1-59593-249-6},
  keywords = {2006 banff d4.1 dynamics imported tagging tags userbehavior},
  location = {Banff, Alberta, Canada},
  pages = {181--190},
  publisher = {ACM Press},
  timestamp = {2007-04-10T15:40:05.000+0200},
  title = {tagging, communities, vocabulary, evolution},
  year = 2006
}

@article{baldassarri:118002,
  abstract = {We present results from a series of experiments on a granular medium sheared in a Couette geometry and show that their statistical properties can be computed in a quantitative way from the assumption that the resultant from the set of forces acting in the system performs a Brownian motion. The same assumption has been utilized, with success, to describe other phenomena, such as the Barkhausen effect in ferromagnets, and so the scheme suggests itself as a more general description of a wider class of driven instabilities.},
  added-at = {2006-10-17T19:20:31.000+0200},
  author = {Baldassarri, A. and Dalton, F. and Petri, A. and Zapperi, S. and Pontuale, G. and Pietronero, L.},
  biburl = {http://www.bibsonomy.org/bibtex/2f0e5fd0f0eba8d57eb8d2f0089ef7b9e/andreab},
  eid = {118002},
  interhash = {bda33ee7fdfab973b4ea22579aa0a79f},
  intrahash = {f0e5fd0f0eba8d57eb8d2f0089ef7b9e},
  journal = {Physical Review Letters},
  keywords = {2006 cnrbest5 experiments fluctuations friction granular model myown prl statistics stick-slip},
  number = 11,
  numpages = {4},
  pages = 118002,
  publisher = {APS},
  timestamp = {2006-10-17T19:20:31.000+0200},
  title = {Brownian Forces in Sheared Granular Matter},
  url = {http://link.aps.org/abstract/PRL/v96/e118002},
  volume = 96,
  year = 2006
}