Elisa blocks depiraatbaai.be, but creating a new domain name for TPB would be trivial.
DNS blocks are not effective.
Same kind of thing has happened with email. Due to the way spam blocking works, the companies that provide email sending services have started to police the traffic themselves.
It's an arms race that cannot be won by censors, because the entire infrastructure has been built on loosely-coupled nodes and technologies that can be encapsulated or mimicked.
The Chinese are getting closer and closer to a breaking point, as more people find out how the "real" internet feels like (either by travelling or by finding ever-easier tunnelling technologies); as soon as the economy slows down and people start grumbling, the gates will fall. It's sad that other countries are trying to go the opposite way.