Could S.978 put Justin Bieber in jail? No.
Free Bieber claims that under this new bill, people who upload covers of songs to YouTube (like how Justin Bieber became famous) could go to jail for five years.
The problem is the Free Bieber website is completely wrong in its assertions and appears to be making inflammatory statements without any knowledge of the law. Uploading videos to YouTube that contain copyrighted material (like song covers) has always constituted copyright infringement if you don't have permission to use the song. It has always been technically against the law (and whether or not song covers fall under the Fair Use exception is a gray area). This should not be news to anyone. But it is not something that has ever been actively pursued for prosecution. Generally, if a company or artist wants material taken off YouTube, they go after YouTube to remove it, not the 14-year-old kid covering the song in his bedroom. This new bill does not target those individuals.
The bill is meant to target streaming video (it's called the Commercial Felony Streaming Act) of copyrighted material (like TV shows and sporting events) for financial gain. If you go online because you missed the latest episode of "Dexter" and you find a stream of the episode - the person/website streaming that video is the one the bill is targeting. They also aren't targeting entities that stream video, but don't receive any financial gain. Sites that stream videos for free and without ad revenue would not fall under this purview.
Copyright attorney Terry Hart explains the the bill and why Justin Bieber would be in no danger if he was uploading the videos that made him famous today. And a spokesman for Sen. Amy Klobuchar of Minnesota affirms, "The bill does not criminalize uploading videos to YouTube or streaming videos at home."