I wonder how they are doing this? We know that the Germans allow full internet access (don't they?), so they can't be using a filtering http proxy. I guess they're blocking on IP number (and perhaps port).
One ISP uses a filtering proxy which still can access xs4all, while blocking the HTTP port to www.xs4all.nl for their users. Others simply block the IP number. Of course, everyone still can use the mirror sites, the anonymizer, open proxies, free Lynx accounts and www-by-mail services. The prosecutors don't seem to understand that yet.
might be a good idea for xs4all to gather up all of their spare IP numbers, and alias the lot on their web site - this would increase the number of blocked addresses needed.
They are already rotating IP numbers. :)