The problem with SOPA and PIPA is that ANY site that is deemed to have access to the intellectual property of someone else can be sued into non-existence even as a hyperlink. For instance, a person on here has a link in their signature that goes to Megaupload. Mega Upload has a clip hosted and uploaded by someone else that has music in the background that is owned by another company. That company can get Mega Upload, and even this site closed down. Even worse, a competing company can have an employee host a clip with their own product and put a link to it on their competitor's web site and get them shut down. It's a great tool for a big company to kill competition.
"I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it." Thomas Jefferson