ODR means "Online Dispute Resolution". Dialogue, negotiation and mediation are coming back as sources of contemporary law. We introduce in this paper two concepts and two related projects. We define the concepts of "relational law" and "relational justice". And, at the same time, we describe how to put them in place from a social and technological point of view. Therefore, we introduce two concrete applications: (i) the Catalan White Book on Mediation, a large project to assemble the required social and legal knowledge to draft a general statute on mediation (Catalan Government); (ii) the Ontomedia Project, a semantically-driven platform allowing end-users to negotiate and mediate their conflicts in several domains (family, commerce, environment, health care, administration…). The paper describes the state of the art of ODR services, and proposes some strategies for legal electronic institutions. A middle-out theoretical approach and a mediation core-ontology are briefly described. We situate these two projects within the next generation of Semantic Web services, and the so-called Web 2.0 and Web 3.0 developments
