Filtering and blocking based on specific URLs and blacklists is a real pain, believe me I've done it plenty of times on a corporate level for people. There are costs involved for a start which I presume will probably end up being paid by the customers of the Australian ISPs i.e ordinary Aussies who just use the internet. There is a speed impact as this filtering obviously takes some time, not noticeable for a small list but just wait until it gets bigger. Every place I have ever seen internet filtering implemented, begins small and then the issues and the decisions soon grow and grow, purely because by starting this filtering you are implying that everything else that is not blocked is acceptable.
Becoming the guardian of the Internet is not something the Australian Government can hope to achieve, all they will do is start down this slippery slope of censorship following countries like Iran and China. Technically they will block such a miniscule amount of illegal or unacceptable content that it really is utterly pointless. They will waste money, create bureaucracy and slow down the average Australians access to the internet for little gain - I'm afraid the Australian Censorship of the Internet is just a very bad idea.
According to Paul Ducklin, Head Of Technology at Sophos, Asia
SophosLabs finds an average of 23,500 newly-infected and actively dangerous URLs every day. These are not hard-to-find child pornography sites, but right-in-your-face risky content hacked into otherwise-legitimate web pages. In 2009, a legislated project to to block 1000 URLs at the core of Australia's internet infrastructure, even if every URL is genuinely and currently bad, is simply a waste of time and effort.
Paul speaks a lot of sense about this issue, his blog is definitely worth a read - here. Just think about it, they are blocking URLs which constantly change, can be redirected in a second, bypassed, cloaked and hidden in innumerable ways. 23,500 found by Sophos labs alone in one day, what if the government received a list of even 20,000 urls containing child pornography every week ?
Do they add them all to the list? Of course if they don't, the Australian Government are in some sense approving these other sites (which of course they don't). It's unmanageable and impractical, without being prepared to throw huge amount of resources at the problem you really are better not following this path of censorship.
It is inevitable I'm afraid, that there will be some people who will want to access this content, the criminals and paedophiles will unfortunately easily bypass these restrictions. Using proxies and anonymous surfing tools even us people who just want to protect our privacy will simply not be affected by this censorship. The Australian Government will simply waste money, resources and end up just creating an Australian Intranet which will just punish ordinary people just using the web for everyday purposes.
The sheer waste of time of this scheme is probably best highlighted by the fact that the vast majority of illegal and criminal pornography is distributed by P2P filesharing, email, chat room, FTP and numerous other methods of which this Australian Censorship scheme conveniently just ignores.
Of course it's much easier to just update a blacklist than actually tracking these criminals down, arresting them and locking them up. The truth is something that Paul Ducklin also points out that it's a much better tactic to protect the endpoint. Software that can be configured on the client PC is much harder to trick as it deals with the actual content being delivered, it can also use the PCs processing power, can be configured by the user and gives them control in order to protect young people using the internet at home.
This means that your government then can't control what you access which I suspect is the reason this solution will never be implemented. No the Australian Government will probably stick with their technically flawed and ill conceived plan to start censoring the internet using individual Urls.
If you're in Australia and want to protest, the best information I could find is on this site - Australian Blackout