Advertisements are objects or media whose purpose is to call favorable attention to things separate from themselves. As a usage it is applied mostly to sign towers (especially billboards) where the sign's function is mainly to promote something. However it can be applied to buildings as a secondary use if a large portion of the facade is covered with one or more advertisements.

This usage does not apply to logos and signs calling attention to the presence of an object in the immediate vicinity. Those are generally classified as labeling.

The promotional subject is distinct from the sign's immediate setting. Labeling identifies a nearby object or its presence, while an advertisement seeks favorable attention beyond that immediate identification.