The Center for Democracy and Technology is coming to loggerjams with the Office of the Attorney General of the State of Pennsylvania. They are trying to use legal proceedings to get information about which web sites might be unreachable because of an effort on the part of Pennsylvania to block web sites that allegedly contain child pornography.
The state is blocking Internet Protocol (IP) addresses rather than specific domain names. It's not unusual for more than one site to share an IP address with a number of others. Actually, it's fairly common these days. It's quite possible that there are innocent sites blocked because the effort on the part of Pennsylvania.
A study released in February by Harvard Law School's Berkman Center for Internet & Society concluded that because modern Web standards permit thousands of domain names to share one Internet address, blocking illegal sites tends to lead to innocuous ones being targeted as well. It said the practice of Web sites sharing IP addresses is so commonplace that Yahoo hosts 74,000 Web sites at one address and Tucows.com uses one address for 68,000 domains.