If advertising is the visible face of a brand, then the craft known around the world as “PR” is the invisible one.

Since the early days of PR, when Edward Bernays succeeded in breaking the age-old taboo against women smoking in public by turning New York’s famous Easter Parade into a mile-long demonstration of “women’s liberation,” with one glamourous woman after another puffing happily away in the spring sunshine, the PR business has aimed at what Bernays liked to call “engineering consent” on behalf of its clients.

PR often works closely with the news media, “planting” favorable stories in newspapers and on TV. Communication is generally much more effective if it is seen to come from an “impartial” source, such as a news broadcaster, rather than through a blatantly commercial message. However, as consumers become more savvy, and more cynical, about the media, they are often able to see through this ruse and recognize planted stories for what they are.

Many times the tactic is not to promote a brand overtly, but to sway public opinion in order to leave people more receptive to commercial messages that may follow. For example, if a PR firm can persuade news channels to increase their coverage of events that raise public anxiety, the public may respond by supporting one of the PR firm’s clients, which may be a security firm, a maker of antidepressant drugs, or a right-wing politician.

While the methods of PR are varied, the goal is the same: to get something to happen, to get people to agree that it is good, and to leave people unaware of how much their point of view is being influenced by someone else. PR operations like to stay unseen because a large part of their effectiveness comes from the public not fully grasping that their opinions are being manipulated.

In The Fall of Advertising and the Rise of PR, Al and Laura Ries advance the argument that while advertising was once a powerful tool for building brands, nowadays publicity is more efficient and effective for generating new interest in a product, with advertising relegated to the role of maintaining a brand that is already established.

In the service of consumer brands, PR is generally used to achieve nothing more sinister than increased sales. Two of the more frequent activities of PR include setting up and financially backing a promotional event, and sponsoring a sportsperson or sports event. In both cases, the goal is to gain a visible presence with a relatively small audience that has a common interest, and to promote the client’s brand by associating it with that athlete or event. The value of the sponsorship or event is then extended through use of the resulting images in advertising.