Sticker art is a form of StreetArt in which an image or message is publicly displayed using stickers. These stickers may promote a political agenda, comment on a policy or issue, or comprise a subcategory of Graffiti.
Also referred to as "labels" or "slaps." A sticker (often obtained from shipping companies and name greeting labels) with the writer's tag on it. Stickers can be deployed more discretely than other forms of graffiti, making them a popular choice for public places such as crosswalk signs, newspaper dispensers, stop signs, phone booths, etc. A popular sticker that was used originally was the "Hello my name is" red stickers in which a writer would write their graffiti name in the blank space. Reflector stickers, found at hardware stores are sometimes assembled to form a crew meaning, or individual writer's moniker. (Wikipedia)