DYNAMICS OF USER NETWORKS IN ON-LINE ELECTRONIC AUCTIONS.
The network of users in the Internet auction site Aukro.cz is analyzed. We show that
the fluctuations in the activity of users has non-Gaussian distribution with long-time
correlations. The bipartite network of auctions and users has degree distribution following
a stretched exponential. The networks observed within a short time windows are
highly fragmented and their structure exhibits long memory, which is observed in the
power-law decay of correlations, with a small exponent around 0.2.