shill
astroturfing
astroturfer
Definitions of astroturfing on the Web:
Astroturfing is an English-language euphemism referring to political, advertising, or public relations campaigns that are formally planned by an ...
en.wikipedia.org/wiki/Astroturfing
The disguising of an orchestrated campaign as a spontaneous upwelling of public opinion
en.wiktionary.org/wiki/astroturfing
astroturfer - One who engages in astroturfing
en.wiktionary.org/wiki/astroturfer