What Howard Rheingold has prophesied with good timing in his book Smart Mobs is concretely realized. In different forms. Groups and self-organized masses by means of mobile devices connected to each other (mobile phones, PDAs and so on) begin to gather in major cities throughout the United States and in London, and are defined as 'Flash mobs' constituting a sort of performance art groups , ready to materialize in one place, to act according to some generic rules and vanish just as quickly. A New York group of 250 people, for example, has just occupied the terrace of the Grand Hyatt hotel after leaving him alone for a few minutes a loud and thunderous applause of 15 seconds, before the police arrived. Who index these meetings, as FlockSmart in San Francisco, generally remains anonymous, and endeavors to meet in locations where it is difficult to do damage. Having previous cases as that of the Critical Mass at San Francisco then extended with some success in Italy (in Milan this year to be exact), these social practices are the result of rapid personal communication and the reconfiguration of urban space always perceived as more usable and manageable territory independently, rather than as a space in which to extricate themselves, as in the past. The rest are virtual communities that materialize, and these actions are the next step to occasional meetings of the discussion groups, effectively breaking the order prevailing social organization, through sudden and unpredictable self-organized actions.