Semiotics.

Semiotics, or semiology, is the study of signs, symbols and signification. Examples of semiotics are, the blue "f" internet icon for facebook or the "w" for wikipedia. An example of semiotics used in music magazines is the red "Q" that always appears on the front cover of Q magazine. This particular icon has never been changed and the distinctive red colouring makes people associate the red "Q" with Q magazine.