I gave a lecture on this at a local university on Tuesday night.
This bill is an attempt to combat copyright infringement by way of "blacking out" torrent or other share sites hosted abroad to keep american consumers from getting at them once those sites are determined (by an american court) to have no substantial purpose other than promoting infringement. The big problem is the potential for abuse - but you still have to have a court order before you can serve a "blackout" order to ISP, DNS registrar, web hosts, etc.
Bear in mind, though, that this isn't the Gub'ment stepping in to tell you what you can and cannot look at online. This sort of action would have to be brought by individuals/companies/corporations that hold the copyrights that are being infringed. By law, the government is expressly prohibited from claiming copyright protection in its own works, so they're not going to be able to claim authorship in something like the governmental memos/reports published by Wikileaks to effect a blackout of that site.
Also, the requirement that the individuals get a court order is actually more restrictive than the current provisions we already have in place under the Digital Millennium Copyright Act (which came about by international treaty back in 1996). All you have to do to file a "take-down" request under the DMCA (which is the current law) is to file a request with the company that is hosting the content - there is no court order required. However, the DMCA can only be implemented to remove content hosted by companies subject to US law. The purpose of SOPA is to come up with a solution to the problem of content hosts (torrent sites, etc.) that are outside the jurisdiction of US courts. To call this "censorship" perpetrated by the government or a particular political party is a mischaracterization, in my opinion. This debate is becoming just another example of the political tools used by both sides to polarize the populace.
I also agree that it's not going anywhere in its present form.
