Just like a database has characteristic signatures, so do words and music.
I have been using Soundex for many years to find words that “sound alike” surnames, and now they have a way to analyze the “genome” of music and find songs that sound alike.
The online music web site Pandora will analyze music that you like and recommend other music that sounds like the music that you like, sort of an ad-hoc recommendation engine that customized a “station” based upon your listening preferences.
Anybody my age will tell you that very little good music was written after 1975, but the oldies stations tend to play nauseating disco.
I paid the $36 a year, and it’s quite good. I doubt that it is really sophisticated music tonal analysis, but rather a sophisticated feedback engine, but it’s quite good, highly recommended.