It's basically a reiteration of the COICA (Combatting Online Infringements and Counterfeits Act) bill that was shot down last year.
It would hand the internet over to the entertainment industry. Any website that "facilitates piracy" if not allowing piracy outright could be shut down by the US government, inaccessible by the rest of the world. No trial. What qualifies a website to be shut down is totally left to the discretion of corporations and the US government. If the RIA says that a lyrics website is violating copyright, the US government pushes a button and *poof* it's gone. Google, YouTube, Megaupload, Mediafire, Piratebay and many more would all be in danger of having their years of building reputation and credibility wiped off the face of the earth without a chance to defend themselves. If a website should be "switched off" so to speak, the owners would only get their due trial when they try to reverse the decision.
It's a breach of international law in that the website would be erased for the entire planet. It's a breach of personal liberties and free enterprise because most websites like Google only serve to index sites. Some call it "facilitating piracy" but I wouldn't say that's necessarily the case. YouTube does its best to take down videos if a copyright claim is made, but they can't catch everyone. Lastly it puts the US government in bed with corporate interests, which is bad no matter who you ask.