So lets say for the sake of arguement that an artist sends the admins of PDfSP forums a email saying you need to remove the images he created.
The law in question doesn't say anything about requiring to sent the owner of a website a notice before it gets taken down.
Under "SEC. 5. VOLUNTARY ACTION AGAINST WEBSITES STEALING
19 AMERICAN INTELLECTUAL PROPERTY." the law sets out a process in which an ISP can simply block you.
That section is the real problem. Lawsuits are expensive. At the moment the internet is ruled pretty much by anarchy.
If you want to block an IP address that's possible provided you know the right people. It's done at the moment.
Then there's the little thing called the law. Comcast thinks that it could get sued if they simply went and blocked all websites they didn't like.
In this law the want to install the right to simply block websites that violate the Comcast's intellectual property without a chance of getting sued.
At the moment a company like DropBox hosts a lot of copyrighted material that get's shared illigally. They can't do much about it.
If they get a notice for taking down material they do so.
RapidShare would another company that acts similarly.
I wouldn't want to have laws that allow the destruction of either of those company who can't do anything about the fact that their services are partly used for violating copyrights.
While rereading the law it doesn't seem to say anything about blocking IP addresses.
Maybe it should be renamed into NameCoin promotion law.