Well here's another criminal activity supporting product...
http://www.hide-my-ip.com/faq.shtml
Basically they set up a proxy IP for a user so the end web host cannot tell who the real user is.
I have to sort of revise what I said about this service prior as I just thought of something.
First of all if you don't want these unknown Ips hitting your sites - block them out. They cannot change the IPs that fast and get so many that you can never block them all - because that would not be cost effective - to continually switch networks like that. The only way they could change IPs that fast is if they were doing some sort of criminal activity to get those IPs by hacking in and using IPs owned by other people. This would be a form of identity theft and very unwise so I doubt this is going on here.
My initial reaction was that that for security reasons, this should be outlawed. If you have to hide your IP address (which can be dynamically assigned from a huge company and always changing anyway) then you are probably doing something you shouldn't be doing.
However there are some instances where this can be used for good. For instance when you are trying to protect your identity because you are reporting criminals and they don't like it, such as I do here.
But I still think this is a hotspot for surveillence of illegal activity.