Fractional participation is an innovative, decisional-associative technique based on the combined action of certain principles (disaggregation-aggregation, cooperation, complementarity, publicity, connectivity, direct involvement, eco-citizenship, agreed acquiescence, cooperative cohabitation, variable role, open leadership, confidentiality, eco-civic-leisure and eco-civic-tourism). It is a kind of virtual, self-instructive political tool that fosters a new dimension of associationism (soft association) and participation (participation à la carte) to strengthen democracy, facilitate its exercise and extend it beyond the realm of the nation-state. The fractional participation instance (FPI) is the prototype of a political tool for exercising fractional participation. The FPI, endowed with the application of the ad hoc software it requires and progressively adapted to the needs of every age, place and circumstances, may eventually become a useful, popular political tool for exercising eco-citizenship. Since this technique functions through the on-going generation of spontaneous open processes that aggregate a series of complementary participation impulses, it could also be called ‘aggregative participation’ or ‘participation through complementary impulses’.