Sujatha Fernandes explains why, in an excellent Znet article on Mexico. "The aim of the Other Campaign is not to tell people to abstain from voting, but rather to point to the limitations of an election where political parties share a consensus on most major issues, and participation is reduced to going to the ballots once every six years. It is to carry the campaign beyond the period of elections to everyday organizing." Community organizing needs to be the center of real politics, otherwise politics becomes the endless reshuffling of elite coalitions.
My own experience is that, in a bourgeoisified American political context, democratic community organizing can be best done through a vehicle like Food Not Bombs, which can cut through the class divisions in a community with the ritual of a public meal. Of course, Food Not Bombs is just a concept; the point is to create a system to arrange public provision of everything. Clothes Not Bombs, Rent Not Bombs, Jobs Not Bombs.