The practice of astroturfing has a long and sordid history. The term was coined by U.S. Senator Lloyd Bentsen of Texas in 1985, referring to a letter-writing campaign orchestrated by the insurance industry. As a matter of fact, astroturfing has been a major tool of political dirty tricks since the Roman empire.
A class of software called "persona management software" magnifies the effectiveness of each paid fake opinion writer by auto-generating a credible but phony online persona, also called a "sock puppet," including a fake name, email address, web site, social media profiles and other data. The software creates fake online activity to give the non-existent users a "history" or online "footprint." Persona management software specific to social networks is called a "social bot."
Some industries rely almost entirely upon web-based reviews, and so astroturfing is rife. Hotels, restaurants and books are heavily reliant on customer-generated reviews to attract new business.