What would be the art form inspiring the style for a song instead of a poem? Isn't a song just a different art form for a poem?

What would be the art form inspiring the style for a song instead of a poem? Isn't a song just a different art form for a poem? For example, The Black Eyed Peas song "Where is the Love", how would that be described artistically to convey it's message of intolerance, injustice? There is poetry that have certain stylistic forms, so how could I categorize this song into what art form?