Came across this on youtube (sorry if it has been mentioned somewhere here already), and thought it was interesting, and disappointing too.

It compares two exact CDs, one pre-mid-90s, and one since then. It tries to show that music is being recorded louder to be competitive, but results in less definition/spikes if the sound is constantly maxed out during (re)recording.

Not sure if this is true though, but if it was, I thought it was interesting (for those who still buy CDs), who may need to look for older releases to get better quality sound.