According to Hit Song Science, they are not trying to make all music sound the same. Their thesis is that all successful music (people like it) has similar patterns, and your song will need be similar to existing successful music:

Historically, what is pleasing to the human ear has not changed since man began writing music... every new style of music that has come into being: country, rock, punk, grunge etc. have all had similar mathematical patterns and the hits in those genres have all come from the same hit clusters that exist today and anything that has fallen outside of those clusters has rarely been successful for it's musical qualities. (Hit Song Science FAQ)

(From Charting the hits - is your song in the sweet spot?)

The software can be used to track trends in musical tastes; the "hit clusters" are examined for new patterns and feeds back into their results.

Science fiction writer William Gibson wrote about an artificially intelligent computer system that could predict musical taste and come up with a "hit." In Neuromancer, Zion is an orbital habitat, spun to make gravity for the inhabitants. It was started by Rastafarian workers who refused to go back down to Earth, and started building with whatever they had. It was not like the spinning space habitat from 2001: A Space Odyssey. And they didn't play classical music, either:

As they worked, Case gradually became aware of the music that pulsed constantly through the cluster. It was called dub, a sensuous mosaic cooked from vast libraries of digitalized pop; it was worship, Molly said, and a sense of community.

This music may or may not have been created with human intervention. However, this second passage refers to music created by an AI (Artificial Intelligence):

"Voices." The Founder from Los Angeles was staring at Case. "We monitor many frequencies. We listen always. Came a voice, out of the babel of tongues, speaking to us. It played us a mighty dub."
"Call 'em Winter Mute," said the other, making it two words.
Case felt the skin crawl on his arms...
"You ever hear this voice before?"
"No," said the man from Los Angeles, "and we are uncertain of its meaning. If these are Final Days, we must expect false prophets..."
"Listen," Case said, "that's an AI, you know? Artificial intelligence. The music it played you, it probably just tapped your banks and cooked up whatever it thought you'd like to --"
"Babylon," broke in the other Founder, "mothers many demon, I an' I know. Multitude horde!"

Music fans are similarly scandalized; the buzz in this discussion on Slashdot is almost uniformly negative. On the positive side, HSS was able to predict the success of an artist like Norah Jones, despite industry scepticism. What do you think? Share your comment below.