Grassroots

A grassroots movement (often referenced in the context of a political movement) is one driven by the politics of a community. The term implies that the creation of the movement and the group supporting it are natural and spontaneous, highlighting the differences between this and a movement that is orchestrated by traditional power structures. Grassroots movements are often at the local level, as many volunteers in the community give their time to support the local party, which can lead to helping the national party. For instance, a grassroots movement can lead to significant voter registration for a political party, which in turn helps the state and national parties.

Read more about Grassroots:  Organizational Techniques, Origins, Astroturfing