The main mechanism of the bill is to interfere with the Internet's domain name system (DNS), which translates names like "www.eff.org" or "www.nytimes.com" into the IP addresses that computers use to communicate. The bill creates a blacklist of censored domains; the Attorney General can ask a court to place any website on the blacklist if infringement is "central" to the purpose of the site.
To draw an analogy, this is like ordering someone's phone line to be disconnected based on a simple court order. It's not a good plan even if it were limited to sites that were clearly infringing copyright. Shouldn't the site owner get a day in court before their access is cut off?
Needless to say, I don't think we should have a DNS blacklist in America. We shouldn't adopt totalitarian information control just to prop up the current crop of companies that are in industry. Indeed, why should we work so hard to prop up yesterday's business models, anyway? We may as well try to bring back the horse and buggy.