In a world of YouTube, iMovie, and digital music tracks, what constitutes fair use? That's the subject of an ongoing struggle between an angry Pennsylvania mother and—essentially—the entire music industry.

As CNET News reports, Stephanie Lenz's attorneys were in federal district court on Friday morning, trying to thwart a motion to dismiss her lawsuit against Universal Music Group; a year ago, the music label ordered YouTube to pull down a 30-second video she took of her infant son dancing to Prince's song "Let's Go Crazy."

At the time, she won the lawsuit, claiming that her video was protected under the Digital Millennium Copyright Act and the Fair Use provision in copyright law. But now she is "out to teach the music industry a lesson," and is countersuing to make sure that they have a legitimate complaint before sending down take-down notices—or face damages as a result, according to the report.

"This video is so clearly non-infringing," said Corynne McSherry, an Electronic Frontier Foundation lawyer, in the article. "What we've seen is that Universal Music had the view that they could take down Prince content as a matter of principle. But what they were obligated to do was form a good-faith belief that the video was infringing... They may not have formed a good-faith belief at all."

(Image credit: Electric Roulette)