The soundtrack of my life

The other day I woke up singing (in my head, of course) Blue Bayou (the Linda Ronstadt version, of course). Then later in the day, I found myself humming Rhinestone Cowboy. This morning, walking to the bus, I started humming Cats in the Cradle, by Harry Chapin. The odd thing is, I haven't been listening to the radio at all, especially not a station that would actually plays these songs (although I do LOVE Linda doing Blue Bayou). So where is the music coming from? Commercials? Maybe. I noticed that a Hem song I like is the soundtrack for that "play it forward" commercial by some insurance company. Maybe there IS a tiny radio planted in my brain.