I do love pandora.com, the internet radio station where you can listen to songs of a particular style and rate them to create a station that you completely like.
It has every song categorized with such things as "a large chorus" or "major-key tonality."
However, one characterization that amuses me that it lacks is what the topic of the lyrics is.
One of the stations that I have created which I enjoy listening to, I have labeled "classical religious," and I rate songs so as to exclude all non-choral and non-religious pieces, as well as those I simply don't enjoy.
But the part that amuses me is that I am sure that I thoroughly CONFUSE the station when I say I "like" a Handel oratorio, but then "dislike" a secular piece by him with all of the exact same characterizations! (the station must think I am really really picky...too bad it has no idea why!) :-P