  The Internet infrastructure is not virtual: its distribution is dictated by
social, geographical, economical, or political constraints. However, the
infrastructure's design does not determine entirely the information traffic and
different sources of complexity such as the intrinsic heterogeneity of the
network or human practices have to be taken into account. In order to manage
the Internet expansion, plan new connections or optimize the existing ones, it
is thus critical to understand correlations between emergent global statistical
patterns of Internet activity and human factors. We analyze data from the
French national `Renater' network which has about two millions users and which
consists in about 30 interconnected routers located in different regions of
France and we report the following results. The Internet flow is strongly
localized: most of the traffic takes place on a `spanning' network connecting a
small number of routers which can be classified either as `active centers'
looking for information or `databases' providing information. We also show that
the Internet activity of a region increases with the number of published papers
by laboratories of that region, demonstrating the positive impact of the Web on
scientific activity and illustrating quantitatively the adage `the more you
read, the more you write'.
