In modern times, paint, particularly spray paint, and marker pens have become the most commonly used graffiti materials. In most countries, marking or painting property without the property owner’s consent is considered defacement and vandalism, which is a punishable crime. Sometimes graffiti expresses social and political messages and a whole genre of artistic expression is based upon spray paint graffiti styles. To some, it is an art form worthy of display in galleries and exhibitions; to others it is merely vandalism. Graffiti has evolved into a pop culture existence often related to underground hip hop music, b-boying, and a lifestyle that remains hidden from the general public. Graffiti can be used as a gang signal to mark territory or to serve as an indicator or “tag” for gang-related activity.
Controversies that surround graffiti continue to create disagreement amongst city officials/law enforcement and graffitists who wish to display and appreciate work in public locations. There are many different types and styles of graffiti and it is a rapidly developing art form whose value is highly contested, reviled by many authorities while also subject to protection, sometimes within the same jurisdiction.