Here in Australia this is a VERY hot topic at the moment, with the government about to go through first trials of ISP level content filtering. This will be administered (the filter list) by the Australian Communications and Media Authority (govt agency).

My biggest problem is I have not seen a definitive statement from the Australian Govt on what it is they are trying to filter out and protect Australian society from. My biggest concern is that it is not overly transparent at the moment and that it is a pretty easy slip into over zealous filtering because of the subjective nature of morals and ideals that the government may try to uphold.

I am all for filtering out the Kiddy P0rn (or how to make explosives to maximise killing potnetial), it is disgusting and no child should be subject to this stuff but I think the problem lies with how to implement this effectively. There is no way any blacklist (blocking known bad) will stop all of these sites, it is simply not possible due to the rate at which new sites appear on the web, in addition to that what about the mistakes of over zealous filter administrators of adding a legitimate site to the blacklist, for example I seem to remember many posts on this site in earlier times about different AV and content filtering vendors adding antionline to "hacking Sites" lists.