alt Hacker NewsI noticed that audio quality begins degrading above 100% (at least if the media is already at high volume), so it really is a useful concept. I'm unsure what Linux distro I'm recalling this from, but it was useful on my little old netbook from college
The software has to start clipping the audio above "100%", but I use it regularly in say, VLC, because I might want the volume slightly higher without increasing my whole system volume just to hear a quiet section. I rarely notice any degradation at 150%.