Perspective: Hazards of the DMCA - 2002-03-22
The DMCA has a provision for copyright violations. If a party believes its rights are being infringed -- in this case, the Scientologists -- it can send a demand to an Internet service provider anywhere in the chain of access for the offending material. In this case, that was Google (a bit of a stretch, since Google is hardly an ISP). And if the ISP complies, it cannot be held liable for the infringement.
The site that's being blocked, Xenu.net, is in Norway, so it's not subject to the DMCA. The Scientologists can't shut the site itself down because it's outside the United States. So they sent a demand to Google, which is based in California, and the company complied with the request to remove the content from its index. (Google subsequently claimed it had only removed certain pages from the site because of a copyright dispute and that Xenu.net's home page was "inadvertently" removed.)
According to the DMCA, the accused infringers have the right to demand that Google reinstate the content, but there's a catch: If they do, they would also have to agree to the jurisdiction of the U.S. courts.