This is a huge deviation from the DMCA. Under the DMCA if someone puts content under copyright on a website [in a manner that's infringing] the specific individual is the one considered responsible and the website they used to put the information on is given some degree of immunity.

Ex: Jon Doe uploads a music video to youtube, without permission from the band's label. The band's label then sends youtube a cease & desist letter. Youtube has to pull the video. If the label wanted to proceed further they can take action against Jon Doe. If youtube refuses to pull the content, only then do they become liable.

But with SOPA, which happens is a bit different. The band's label goes to the feds. Says "John Doe posted one of our songs without permission on youtube!" Now the feds get what amounts to basically a special court order, sends that to the ISP youtube hosts their website on. If this ISP is an American ISP the website then gets permanently taken down. No more youtube. All because of 1 person who uploaded something under copyright.

It doesn't stop there however. This also extends to all websites that "link to" infringing material. So not only would youtube be potentially deleted from the internets; The feds would have the legal authority to shut down every website hosted in the US which has ever "linked to" youtube. Bye bye basically every American internet forum, google, blogs, newspaper websites, etc.

If I posted a link on BP to a blog article written Jan 1st, and that blog had posted part of a news story under copyright three weeks later: theoretically BP could be permanently shut down by the feds even though it never actually linked to the offending material. Just to the website that had offending material on it.

Another dangerious idea they had considered with this bill was criminalizing the act of downloading content. This is dangerous because people unintentionally download infringing material every day. if you click on a link do you KNOW before hand whether the website uses any pictures under copyright? Do you know if it will have any news stories under copyright cut & pasted onto the webpage? You don't know until after you click on the link [thereby downloading the content]! If I post an image that is copyrighted on page 27 of a 50 page thread: everyone who clicks on page 27 while reading the thread will "technically" have downloaded copyrighten material!