Monetized: Quest for Everything Part 3 http://www.youtube.com/watch?v=kA6obOTgi8o
Not Monetized: Quest for Everything Part 4 http://www.youtube.com/watch?v=PCCkAwgyi8o
Can you tell me the difference for monetization?

Just doing a quick scan through the 2 videos I noticed the video that wasn't monetized contained music.