A signature song is the one song (or, in some cases, one of a few songs) that a popular and well-established recording artist or band is most closely identified with or best known for. This is generally differentiated from a one-hit wonder in that the artist usually has had success with other songs as well. A signature song may be a song that spearheads an artist's initial mainstream breakthrough, a song that revitalizes an artist's career, or a song that simply represents a high point in an artist's career. Often, a signature song will feature trademark characteristics of an artist and may encapsulate the artist's particular sound and style. Signature songs can be the result of spontaneous public identification, or a marketing tool developed by the music industry to promote artists, sell their recordings, and develop a fan base. Artists and bands with a signature song are generally expected to perform it at every concert appearance, often as an encore on concert tours, sometimes being the last song of the setlist.