Aiseca : After an investigation, this is the result :

29% - Comments that says that the Vocaloid who is singing in the video was sooooooooooooo Kawaii with all the 'XD's' they could attach.

30% - "UR WRNG IF YOU DON'T LIKE VOCALOID"

20% - are the "Shipping Wars" where they extract all the needed ammo in who's Vocaloid should be shipped with, defending their ships against other shippers. The toughest of the ships would set sail and prevail. (Mostly in the Secret Len Fandom World)

20% - The Len Kagamine Worshippers. The sentence us enough to explain the rest.

1% - The comments regarding the actual vid.

Well that's the perspective of the informant. I don't know if it's accurate (well the Len thing is unquestionable. Maybe bigger percentage than that.) But ...... maybe it does reflect..