The Finnish variation is a DNS blocking system ostensibly targeted at child porn. The system is however very dubiously implemented using secret block lists maintained by the police, and it blocks access to many sites that contain fully legal content. A well-known case is the police blocking access to the website of Matti Nikki, an anti-censorship activist.
There has been also discussion of expanding the system to block access to other internet resources, like gambling or file-sharing sites.
As is usual, this kind of faulty, and easy to circumvent system is the product of decision makers being ignorant of technology, even in the age of the information society. There was a demonstration today at the Finnish parliament house with about 500 attendees:
(picture source: Helsingin Sanomat)