Astroturfing

A basic explanation is this: if a grassroots movement grows upward from collective efforts, on a local level, of dedicated people donating their time and efforts to further a political or social cause they deem to be good for the many, then Astroturfing (Astroturf being an artificial grass) is an artificial grassroots movement, one that is made to appear as though it is a real grassroots movement, but it is usually done to advance a cause for the benefit of specific individuals or group(s), and most often not at a local level.