Board Thread:Questions and Answers/@comment-2602:306:333F:7CD0:AD42:C620:D7B2:765E-20171120082803/@comment-53539-20180104191051

A lot of the youtube uploads aren't official so they can be prone to removal randomly. Music often is protected by law from such things. SEGA often gets random spouts of removal urges for their games songs, but can get a little overboard at times.

Nico video is definitely the place to haunt. More vocaloid songs uploaded there daily and generally most producers in Japan have their stuff there.