The whole concept of an "untraceable website" or the idea that such a thing would be unstoppable by ISPs and law enforcement is absurd--the immediate upstream provider of the site would merely need to null route the IP address(es) where the website is hosted, and traffic stops. They'd also be able to quickly identify the customer who owns the server in question. Even if that server was compromised and being used to reverse proxy or redirect traffic to other servers, it would still be a relatively simple matter to track that backwards, though it would be somewhat more difficult than stopping the traffic. Even if the domain name pointed to a new server on a compromised host every second, it would still be possible to contact the domain name registrar and get the domain name shut down.
If users can get to it, it can be seen how and what they're getting to, even if that's only the front end in a chain of successive proxies. If it has a domain name, that provides another path to shutting off access.
UPDATE (January 2, 2008): I came across the script online while searching for information about the writers. Let's just say that my opinion above is not nearly negative enough. In the first 16 pages are at least six or seven scenes that really bring on the stupid. For example, FBI Agent Jennifer Marsh, who works in the FBI's cyber division, is monitoring machines that are being compromised by hackers (honeypots, essentially, though the script doesn't use the word). One of her machines gets compromised and she sees that it copies her files including fake financial information. It then accesses eBay to use a stolen credit card to purchase a watch. In reality, the stolen financial information wouldn't be likely to be used from the same machine, it would be sold to another player in the underground economy. Marsh then types commands to look for the IP address of the connecting host--but if they've already got honeypots or honeynets in operation, that should already be logged. She then does the usual CSI-style conversion of an IP address into a name and address without issuing a subpoena to an ISP, and discovers that it's a home belonging to a 56-year-old woman. She immediately concludes that the actual criminal must be a neighbor using her wireless connection, despite the fact that she has no evidence that the woman has a wireless access point and isn't just another victim with a compromised machine being used as a proxy. Without doing any more verification, she arranges to get a warrant to knock the door of the neighbor down, and it turns out to be a teenage kid.
On p. 16 appears this nice quote: "She types several commands into a unix shell. Trace routing algorithms begin to run. A different screen shows possible IP addresses. The list begins growing, from ten to hundreds to thousands.... Marsh shakes her head at the futility." There are multiple methods of performing traceroutes and even of adding fake hops to a traceroute, but traceroute is unnecessary to find out the IP address of a website--it's only useful for finding the path traffic takes to get to that website, e.g., for finding the upstream provider. But getting a list of upstream providers is better done by looking at routing tables rather than doing traceroutes, anyway. The real investigative steps would be to look at the DNS information for the domain, get the IP address or addresses from the authoritative name server (and check to see if those are changing with a short TTL), then find the upstream providers.
Funniest exchange I've seen so far in the script (p. 26) is this marvel of self-contradiction:
[FBI agent] GRIFFIN: I traced it to a Georgetown sophomore named Andrew Kinross. But then I looked closer and saw the post didn't actually originate from his computer.And so far, I've not mentioned how the hacker mastermind hacks into the FBI agent's car (which features the fictional "NorthStar" instead "OnStar")--in the preview, the hacker apparently is able to control the steering of her car. I suspect drive-by-wire steering will come soon in the future of the automobile, but I don't believe it exists today. (Turns out the preview gives a misleading impression of what the script says is happening--the hacker doesn't actually control the steering, but remotely shuts off the car's electrical systems and power steering.)
MARSH: Our guy got into his computer and posted it from there.
GRIFFIN: That would be my guess.
MARSH: So let's go after the originating computer's IP.