Abstract: Search engines have become key media for our scientific,economic, and social activities by enabling people to access information on the Web in spite of its size and complexity. On the down side, search engines bias the traffic of users according to their page-ranking strategies, and some have argued that they create a vicious cycle that amplifies the dominance of established and already popular sites. We show that, contrary to these prior claims and our own intuition, the use of search engines actually has an egalitarian effect. We reconcile theoretical arguments with empirical evidence showing that the combination of retrieval by search engines and search behavior by users mitigates the attraction of popular pages, directing more traffic toward less popular sites, even in comparison to what would be expected from users randomly surfing the Web. We then extend the analysis of traffic to a general model of search-driven network growth, that predicts the topological propertied of the Web graph. Joint work with Santo Fortunato, Alessandro Flammini, and Alessandro Vespignani.