Stephanie Lenz uploaded a video of her child dancing to Prince's tune - Let's Go Crazy, to YouTube. In the video, the child is seen making moves, while the song is played in the background. The video was uploaded in 2007 on YouTube. Universal Music, the owner of the sound recording, was not too happy with the use of the music in the video, which was getting great attention. UM sent a DMCA take down notice to YouTube, and YouTube…