Astroturfing
Etymology
The word puns on AstroTurf, the brand of artificial grass, set against the idea of a "grassroots" movement — fake grass for fake grassroots. Its coinage as a political term is usually credited to U.S. Senator Lloyd Bentsen, who around 1985 described a deluge of orchestrated mail as astroturf. The internet made the tactic cheap and industrial.
noun · /AS-troh-tur-fing/
The practice of faking grassroots support by disguising an organized, funded campaign as a spontaneous movement of ordinary people.
What it names
A now-routine deception: the flood of "authentic" reviews, comments, or citizen letters that were actually manufactured by a company or political operation.
Example
The sudden wave of five-star reviews all posted within an hour had the fingerprints of astroturfing, not genuine enthusiasm.
Related idea
Astroturfing fakes the appearance of a broad public; a sock puppet is one of its tools — a single operator running many fake identities to simulate that crowd.