Sorry i was late

The urge to express oneself by writing on a blank wall is as old and primitive as cave painting.
We as humans have always felt the urge to communicate; we began by scratching into the surface of caves. Throughout time this evolved with the written word. This form of expression is now rife in our society, with so many new ways to 'be heard' why hasn't this technique died out, or is it just part of the human condition?