: For modeling real-life situations where not only the intensity of the relation existing between elements but also its polarity is important, we have proposed (see [Marcus and Tataram 1987a]) a new type of graphs: the signed networks. In the present paper we study two of thier most important properties: connectivity and reachability, and try to use them in order to offer a strategy to improve communication in social or professional groups. Key Words: graph theory, connectivity, geodesics Category: G.2.2, G.2.3