The purpose of a persuasive message is to convince a person or group to undertake a particular action, and good examples of persuasive messages have existed for a long time, such as the De Beers slogan "A diamond is forever." The De Beers company discovered diamond mines on Africa, but at the time diamonds did not have a lot of value, as they were not yet commonly used in engagement rings and had not yet become popular as a romantic gift.
The status of diamonds changed forever in 1938. De Beers' slogan "A diamond is forever" accompanied an ad campaign suggesting that grooms use diamonds to accompany a marriage proposal. Since that time, diamonds have come to take the place as the only acceptable expression of love. Making diamonds seem scarcer than they were, De Beers ensured itself a steady client base with this message, and the artificially high prices of diamonds are still an expense for grooms-to-be.
The Nike slogan "Just do it" has become just as popular in modern parlance as diamonds, but Nike was not always a dominant sporting goods giant. The late 1980s saw Nike barely holding its own against Reebok when the company developed this slogan, weaving it into an ad campaign selling the viewer on Nike's mission: athleticism without compromise. This slogan was a major factor in boosting Nike's share of the domestic sport shoe market from 18 percent in 1988 to 43 percent in 1998.