At its best, advertising is story telling that sells a product or service. The story could be told through any number of channels, including online, tv, radio, outdoor, print, etc.
I use the term ‘story’ loosely. It doesn’t have to be a novel. The story could be told in one or two pictures. American Apparel is able to communicate quite a bit using only pictures.
The hero of the story should be the product or service that’s being sold. Notice how the polka dotted pants make the woman appear irresistibly sexy. Nice work, hero.