Why commercials have music?

Why do movies and TV shows have music? Set the tone, help send a message, add background noise? Music in commercials (and TV shows) these days has become a bigger deal than what it used to be to have your song featured on a motion picture soundtrack. People are so in tune to music being played in ads and shows and they want to know who's singing and where they can buy it. It's become a great marketing tool for the music industry to advertise their new artists and it's become a great way for listeners to discover music they love.