First off, with regards to Horness' comment and those telling us that blocking content won't make it go away:
"So if they know what the sites are, and are able to filter them out of your browsing - why the hell don't they shut the sites down carrying the content?"
That would be because the internet lets you access websites in other countries - so if the 7,000 blocked sites are based in countries other than New Zealand then the NZ Govt cannot shut those sites down. While I don't have a lot of time for any politicians, at least most of ours (yes, I'm a Kiwi) don't seem to think that the celestial globes rotate at their command. Some stupid laws certainly get signed into the system, and certainly some do have some very loose descriptions, but I can't think of any examples where laws have been substantially twisted. Kiwis do tend to be a bit vocal when we think Politicians are trying a fast one, so maybe that is why.
For those saying that people will get around the filters that is very true, but that does require at least a little knowledge. My impression is that this law is aimed at stopping this sort of content popping up for casual surfing. Who knows, maybe this will mean that some people who would have stumbled over this type of content and become more interested in it now won't?
Just my $0.02, thanks for reading it.