I'm actually supporting 4chan because if any isp thinks they can block a site just because they feel like it, it would suck.
web filters, that do exactly that, will be placed in Germany by 1st of August... same stuff as in China
though "officially" to block childporn here. However, the list is completely secret - and "every 3-6 months" a few entries are picked out and checked if they really contain childporn...
So well, hello censorship.
If it is a ban of the domain itself - use OpenDNS (google for a manual) to get around.
If it is an IP blocker, use a proxy to get around.
Chinese people can get around, we can too =)