Astroturfing

Astroturfing |ˈastrōˌtərfiNG|
Noun

A form of advocacy in support of a political, organizational, or corporate agenda, designed to give the appearance of a “grassroots” movement. The goal of such campaigns is to disguise the efforts of a political and/or commercial entity as an independent public reaction to some political entity—a politician, political group, product, service or event.

See example.