The ever-changing and growing reality of on-line communications and of the World Wide Web has posed the need for a general rethinking of the tasks of all the participants involved in the process of creating and using a 'cultural product'. Publishers and all those institutions involved in the dissemination and preservation of cultural heritage cannot ignore the risk of being left behind and gradually replaced by different participants who, since they own the new information technology, can become the new, unique vehicles for its dissemination. But the challenge that publishing houses and primary source repositories such as libraries and historical archives have to face nowadays is not only that of safeguarding their experience and know-how, and bringing it into the new information technology world. The change of roles has to involve singling out new kinds of 'cultural products' and value-added services that properly exploit all the potentialities of the new technology. In this paper, we will describe the experience of a publishing house which has moved into the non-traditional sector of on-line publishing. Specifically, we will examine its close collaboration with European libraries and historical archives on the one hand, and with software houses and technical universities on the other, in order to develop innovative editorial services on the World Wide Web.