Advertising is used in many ways. Health experts use advertising to warn the public against bad things. For example, they want to prevent young people from starting to smoke. They assume that young people won’t start if they know how bad smoking is. Sometime, health organizations may want to change people's behavior getting them to exercise more, for example.
However, advertising is more often used by industry to sell things. A company’s income depends on how much money it makes by selling its products and services. These days, the trend is for companies to advertise their brand. A brand is a mark, a name, or a label that stands for a company’s products or services. In the past, a clothing company would advertise a coat or clothing. Nowadays, a company might advertise how people feel when they wear its label. In this way, the company develops 'brand loyalty.' That is when people like to buy only the products from one brand. Then the company can charge more money for its products. Investors in companies like brand loyalty very much because the price of their stock goes up when a company has a strong brand.