If you take a group of people, a subgroup of the larger population, and expose them to focused messages again and again, you will start to change their point of view. If you augment those messages with exposure to other members of the group, the messages will begin to have ever more impact.
If the group becomes aligned, and it starts acting like a tribe, those messages will become self-reinforcing. And finally, if you anoint and reward leaders of this tribe, single them out for positive attention because of the way your message resonated with them, it will become fully baked in.
That's a lot of power. Probably too much for the selfish marketer, lobbyist or demagogue to have at his disposal.