It seems technically unfeasible to do anything like this, there are two potential methods:
1) A list of banned sites - this is unworkable because it would require the cataloguing of every site on the interent, not even google can do this. New porn sites appear everyday this is unavoidable and hence this 'blacklist' is unworkable.
2) A filteration system which scans for black listed words or phrases (it being impossible to use a computer to scan for porn itself as it can not discriminate a pornographic pic from a non-pornographic one. This is also unworkable for several reasons, it is computationally intense at the ISP side requiring the ISP to check all traffic before sending it on. So costly and slows the internet. Furthermore such filtering technology can often inadvertantly exclude non-pornographic content which happens to contain trigger words.
I pose a question to what extent do we filter? If we are filtering porn do we also filter swear words? Perhaps we will do so inadvertantly anyway, by filtering the word 'fuck' to block porn we would also be blocking other sites which used the word in a non-pornographic manner - such as me just now. To what extent do we become a nanny state and pass the responsibility for our children from us (parents) to government. These censorship moves ammount to parents abdicating responsibility for their children to government, it is buck passing and blame avoidance.
Let us suppose that this 'solution' is introduced, there are at least two instances in which parents will have to still filter at the client side:
A) When parents want to view porn, however wish to bar their children from doing so they would need to subsribe to a 'unclean' feed (note the conceptual framing going on with the use of the word 'clean' in discussing this). However they would then need a third-party cliet-side filtering program to block their children from viewing porn.
B) When parents also want to block access to swear-words etc they will again need further filtering.
Perhaps the most interesting aspect of this whole debate (and one that has not appeared as yet) is the prevalence of pornography, we have not seen the stats that show that the majority of men do view pornography and a sizeable proportion of women as well. In fact I would go as far as to say that many advocates of this policy would themselves need to subsribe to an 'unclean' feed. That there are indeed a great many hypocrites out there who view porn behind closed doors so too speak.
Finally to quote a fun song by Trucks:
its just porn mum
and youre runnin away
you wouldnt believe what the kids see today
its just porn mum
and it wont go away
wherever you turn you find porn everyday....
