If you read the intro on the project page a bit further:
"To be clear, neither of the authors truly believe there can be an unchanging "formula" for a hit song, as much of what appeals to us in music is a combination of familiarity and surprise (Sacks, 2006). Currently, intangible notions such as emotional qualities also have a great affect on our experiences with music. However, while there are many outstanding questions, our inquiry may shine some light on a few characteristics that could increase the chances of a good song becoming a hit at a certain point in time."
Slashdot Mirror
If you read the intro on the project page a bit further: "To be clear, neither of the authors truly believe there can be an unchanging "formula" for a hit song, as much of what appeals to us in music is a combination of familiarity and surprise (Sacks, 2006). Currently, intangible notions such as emotional qualities also have a great affect on our experiences with music. However, while there are many outstanding questions, our inquiry may shine some light on a few characteristics that could increase the chances of a good song becoming a hit at a certain point in time."