What Makes a Book Title a Bestseller?

Lulu Titlescorer is a scientific little tool that, based on the attributes of New York Times bestsellers from 1955-2004, allows you to predict the likelihood that a given phrase or title will be a hit. After entering all sorts of jejune possibilities (see above), we decided to analyze some of this week's bestseller lists from the Times and see, retroactively, what sort of chance they had based on title alone.
Hardcover Fiction
The Hostage, by W.E.B. Griffin - 35.9%
The Da Vinci Code by Dan Brown - 35.9%
S is for Silence by Sue Grafton - 44.2%
Mary, Mary by James Patterson - 45.6%
Every Breath You Take by Judith McNaught - 63.7%
Hardcover Nonfiction
My Friend Leonard by James Frey - 41.4%
The Year of Magical Thinking by Joan Didion - 10.2%
The World is Flat by Thomas L. Friedman - 26.3%
Marley & Me by John Grogan - 45.6%
Teacher Man by Frank McCourt - 31.7%
Disclaimer: The Titlescorer depends on very specific grammatical definitions, which made our heads kinda spin. Choosing your definition can greatly affect the resulting percentage, so this is admittedly sloppy.