The graffiti is transformed over the ages. Once viewed as a problem and a sign of crime level in the area, now cities are taking a new course by putting up areas where street art is welcome, or hiring artists who are skilled with spray paint to paint old buildings with super cool murals, check some examples here and here. Of course, graffiti ranges massively in terms of complexity and to appeal the masses, and many argue that by picking what sort of street art is culturally acceptable and should be supported by the law is simply producing a sanitized version of the popular form of expression, as even the most modest scrawls have a goal of expressing an idea, frustration, or simply the joy and wants to be heard by the society.