In the context of economy globalization, the need for globally distributed negotiations involving a high number of negotiators communicating through the Internet becomes an important business issue. In such negotiations, the amount of information describing the negotiation process is too high to be easily understood by humans. In this paper, a prototype negotiation support system adapted to mass e-negotiations is presented. The presented prototype, named NeSSy, is based on a negotiation model consisting of a multi-facet analysis mechanism which provides synthesized views of the negotiation process, allowing to extract knowledge concerning various aspects of the negotiation process.