The expansion of the social influence of the Internet have led both general interest and national public broadcasters to a structural challenge. The new on line paradigm demands a full version of the public enterprise, which include all the available tools to achieve its mission. The Internet would be the ideal complement to the public service. Before this, public broadcasters should define its core business to attend the public demand and to collaborate in the creation of the public sphere. Finally, the clear definition of the public activities and the separation of public and commercial finance will be a main point. To confirm the benefits of the intervention of the public broadcasters we will study the cases of Spain and United Kingdom.