Why do campaigns advertise? Because they have a message that will help them reach new customer, build brand image and increase market share. Advertising is extremely expensive, so companies usually only run a campaign when they enter a new market or launch a new product.
Many campaigns follow the AIDA formula. First, they raise Awareness, that is, make sure that more consumers know the product and what is does. Then, advertisers try to build interest, to persuade consumers to learn more about the product