Finland set up a filter that is supposed to be for illegal material outside their country only, a list reported to be about 1500 sites. Yet, when a web site within Finland put forth an anti-censorship message and provided a section of the banned list, that site itself was banned.

Australia intends to filter all pornography by default. (though you can opt out of that) If Finland's authorities can't be trusted to implement their law when it covers 1500 sites, what sort of public oversight do you think there can possibly be over a list containing tens of millions of entries and growing by hundreds every day? Error rates will be astronomical and those in power would be able to block any site at will and claim it was a random error. The risk to freedom of speech is quite real.