Effect Measure is not safe to visit today. The title of this post draws a pained request from a reader, but the proprietor's response is not at all helpful.
From someone in Metafilter (here) a while back:
I remember reading at one point that having a song stuck in your head stimulates part of your lower brain, and that the dumber and simpler the song is, the more the lower part of your brain likes it. It's like having an inner moron.