The goal of such campaigns is to disguise the efforts of a political or commercial entity as an independent public reaction to some political entity—a politician, political group, product, service or event. Astroturfers attempt to orchestrate the actions of apparently diverse and geographically distributed individuals, by both overt ("outreach", "awareness", etc.) and covert (disinformation) means. Astroturfing may be undertaken by an individual promoting a personal agenda, or highly organized professional groups with money from large corporations, unions, non-profits, or activist organizations. Very often, the efforts are conducted by political consultants who also specialize in opposition research. Beneficiaries are not "grass root" campaigners but distant organizations that orchestrate such campaigns.

The term is said to have been used first in this context by former US Senator Lloyd Bentsen of Texas. It is wordplay based on grassroots democracy efforts—truly spontaneous undertakings largely sustained by private persons—as opposed to politicians, governments, corporations, or public-relations firms. AstroTurf refers to the bright green artificial grass used in some sports stadiums, so "astroturfing" refers to imitating or faking popular grassroots opinion or behaviour.

This practice is specifically prohibited by the code of ethics of the Public Relations Society of America (PRSA), the Public Relations Institute of Australia (PRIA) and the Chartered Institute of Public Relations (CIPR), the national associations for members of the public-relations and communication profession in the United States, Australia and the UK respectively. As private organizations, the most significant punishment the PRSA, PRIA and CIPR can hand out to members who engage in astroturfing is revocation of association membership. Although the International Association of Business Communicators (IABC) does not specifically mention astroturfing, it does require honest communication.

Astroturfing is a form of propaganda whose techniques usually consist of a few people attempting to give the impression that mass numbers of enthusiasts advocate some specific cause. In the UK this technique is better known as "rent-a-crowd" after the successful "rent-a-crate" business.

US Senator Lloyd Bentsen, believed to have coined the term, was quoted by the Washington Post in 1985 using it to describe a "mountain of cards and letters" sent to his Senate office to promote insurance industry interests, which Bentsen dismissed as "generated mail."

The National Smokers Alliance, an early astroturf group created by Burson-Marsteller on behalf of tobacco giant Philip Morris, worked to influence Federal legislation in 1995 by organizing mailings and running a phone-bank urging people to call or write to politicians expressing their opposition to laws aimed at discouraging teens from starting to smoke.

In 1998, a combination of television ads and phone-banks were used to simulate "grassroots" opposition to a bill aimed at discouraging teenage smoking. According to The New York Times, "Those smokers who are reached by phone banks sponsored by cigarette makers, or who call the 800 number shown in television ads, are patched through to the senator of their choice."

In 2003, apparent "grass-roots" letters favouring Republican Party policies appearing in local newspapers around the US were denounced as "astroturf" when Google searches revealed that identical letters were printed with different (local) signatures. The signers were electronically submitting pre-written letters from a political website that offered five "GOPoints" for sending one of their letters to a local paper plus an additional two "GOPoints" if the letter was published. A similar automated emailer employed by MoveOn.org in 2004 to support Michael Moore's Fahrenheit 9/11 film resulted in at least 22 form letters appearing in local papers.

Black propaganda is information that purports to be from a source on one side of a conflict, but is actually from the opposing side. Most astroturfing is black propaganda in that the identity of the source is falsified. However, the ostensible source of the evidence planted is usually not a grassroots organization. When black propaganda uses the same means as astroturfing, the distinction is less clear, as in the case of forged letters being sent to congressman Tom Perriello by a Washington lobbying firm working against 2009 clean energy legislation.

Journalist Ben Smith of The Politico has observed, "Interest groups across the spectrum have grown expert at locating, enraging and turning out authentic Americans. And the operatives behind the crowds say there's nothing wrong with a practice as old as American politics." Regarding the 2009 health care debate, author and blogger Ryan Sager has argued in a New York Times editorial: "Organizing isn't cheating. Doing everything in your power to get your people to show up is basic politics."