This actually seem true and it is amazing. They have chosen a louder standard than iTunes which is sad but that might change in the future. I’m not going to rant about it when others do it so exceptional well (I’m just going to sit here and be happy about it).
http://towerofdoom.net/audiogeek-youtube-started-normalizing-audio-uploads/
http://productionadvice.co.uk/youtube-loudness/
http://productionadvice.co.uk/youtube-loudness-normalisation-details/