Any ideal or action you hope to spread is dependent (at least partially) on the ability of people to call it by its name. Drunk driving was a massive problem back in the 1980s, and several campaigns were put in place to try and teach people about the dangers of drinking and driving. Facts and statistics were used to some avail.

Then they decided to call one person in the group the "designated driver". Simple concept: one person in the group stays sober and gets everyone else home without crashing into a tree. This wasn't a new idea, but the name solified the concept amongst groups of drinkers. The sober person in the group suddenly had something to call themselves when the bartender asked them if they wanted a drink. The DDs could find one another in bars, where they could exchange sob stories about having drawn the shortest straw for that particular evening.

The name, not the idea, changed drinking culture and behavior of the people in it.