Kerning

Kerning refers to the spacing between the characters of a font. Without kerning, each character takes up a block of space and the next character is printed after it. Kerning is useful because it allows more text to be placed within a given amount of space. 

This allows longer articles to be placed in newspapers and magazines with limited space. It also looks more natural because when writing by hand, people often make characters overlap. When kerning is applied to a font, the characters can vertically overlap. This does not mean that the characters actually touch, but instead it allows part of two characters to take up the same vertical space.