Graffiti signatures, also known as tags, are the unique symbols or words used by graffiti artists to identify their work. They are often stylized and can be used to represent an artist's name, initials, or a particular message. Tags are usually written in spray paint, marker, or other materials that can be quickly applied to a surface. Graffiti signatures are often seen on walls, buildings, and other public spaces, and can be used to express a variety of messages, from political statements to artistic expression.