What I'm trying to say is that the number one song doesn't convey a lot of information. The genre of the number one song may be the most popular genre or one of the least popular genres; you can't know if you only look at the number one song. With your example, it could be possible that 0.1% of the population LOVES Beethoven's 5th symphony and exclusively plays it on repeat while the other 99.9% of the population hates classical music. Just to be clear, I'm not making any claims about what's popular or not, I'm just presenting an alternate hypothesis that would also result in the number one song not being representative of the overall population's preferences.