Its worth noting that the law doesn't require ISPs to screen traffic. It merely authorizes the sharing of child porn images for this purpose. Presumably there are ISPs lined up who want to do this but presently its illegal. Soghoian's perl script is a simple example of a myriad different things that can be done to data to make it invisible to this sort of screen. But Soghoian, having already had the FBI break into his house in the middle of the night for pointing out naked emperors, thought better of publishing the code.
If, by some fluke, such a system as this is implemented, they should at least force ISPs to disclose whether they use the service. Would make ISP shopping easier.
I don't see the system as particularly effective in doing what it sets out to do. It may have a chilling effect on the casual runner, but someone dedicated will just circumvent and take further precautions.
What it puts in place is, as noted in the discussion, a technical means to enforce flagging the passage of any "interesting" combination of bits. Definately seems like there would be potential to cast the net wider than the original intention, unless specific language is put into the legislation that prohibits the use of the system for anything except catching child porn. Stipulations would need to be put in that in the event it is abused to catch copyright violators (or someone circulating subersive lit for example) that the evidence cannot be admissable in a court.
Also don't see how the system would scale. How will it handle video? Thing about the IDS signature problem times n.
RE: Thought Crime