Theodore Levitt, a Harvard Business Professor and an Economist, wrote back in 1960 one of the best articles in the world of business, an article titled Marketing Myopia (PDF link).
He said: People don???t buy products, they ???hire??? products to do a particular thing. For example, people don???t buy a drill, they buy a hole. They ???hire??? the drill to make the hole.
the article is about the digg redesign – but most of all i love that quote.