When you add steamed milk to a shot of espresso and then top the cup off with foamed milk, the result is cappuccino. The drink is named for the Capuchin monks, whose habits contain similar shades of white and brown. In Italy cappuccino is considered a good drink for breakfast, but elsewhere in the world it is drunk at all times of night and day.
Coffee purists might consider cappuccino, along with mocha, latte, flavoured coffee etc. to be adulterated coffee, designed to mask the deficiencies of the basic brew. While I would tend to agree with this viewpoint, it is certain that many people prefer the creamy consistency of a cappuccino to purer forms of coffee, and if really good coffee is unavailable, why not chuck in a bunch of stuff to make it taste better.
I would not consider myself a coffee purist, as I add a very small amount of both milk and sugar to my coffee, but the taste I enjoy is the coffee itself.