The Paris European Social Forum (ESF), which took place in November 2003, was the second such continental gathering since Florence in 2002. Yet much of the political energy of Florence was lacking. Why was this? The author argues that the social forum is caught between a desire for greater ‘inclusivity’ and the need to develop political strategies that can affirm the guiding rationale of the social forum process, i.e. that ‘another world is possible’. The London ESF, due to take place in October 2004, needs to reassert the primacy of the political over the social function of the ESF, and to help promote forms of activism that offer a genuine challenge to the corporate takeover of the planet.