bapu
slartabartfast is a buzz kill.

The video is cute.
I couldn't agree more to both statements.
Nonetheless, why is a service that, from any objective standard, makes a substantial portion of its income from a barely masked soliciting of copyright infringement not forthcoming with what exactly it means to have an ad appear on your contribution instead of a takedown notice? I am not criticising the artist here, he may have negotiated the license with the copyright owner prior to posting to YouTube for all I know, but I am offering a caution to those among us who are not interested in learning the issues involved that just not having your YouTube posting removed does not necessarily mean that you are free and clear. The issue in this particular case is probably a no-harm-no-foul one. A significant factor in the test for fair use is whether the original work is going to be a substitute for the original and hurt its market. But there are undoubtedly songwriters who would not want their melody used for an ISIS recruiting song and video who could see the implications of this discussion as less than cute. If the test becomes what you can get away with instead of what is the law, then anything is OK, cute or not.
And the derivative works issue is a major stumbling block for many people. You can get a license to cover another author's song in its entirety without having his consent, but if you sample two seconds of his recording of the same work, you are in trouble. That does not make any more sense that that a photograph of a statue requires a license from the sculptor, or that making a sculpture based on someone else's photograph of the subject requires a license from the photographer, but artists have lost money and control of their own work based on those facts.