Although I respectfully disagree with Sven’s take on the internet and porn*, his opt-in porn policy is certainly better than China’s draconian attempt to “clean up the internet” by shutting down pornographic websites and opening over two thousand criminal investigations. (Good luck, China! And when you are finished, I’m sure you’ll move on to easily and successfully end the scourge of drug use).
What is more disturbing to me is the technique used to get the “bad guys” – paying people to become informants on those trafficking in porn. According to CNN, 534 people received “rewards totaling 544,000 yuan (U.S. $81,964) for providing information.” This technique is destructive of human sociability and friendship in the service of a contestable end and of a mission that is very, very unlikely to make a dent in the use of pornography. Moreover, it doesn’t take a rocket scientist (or public choice theorist) to see how the use of informants can be abused and lead to all kinds of problematic consequences. You would think that a place that went through the Cultural Revolution would think twice about such things, especially for this type of “crime.”
So, chalk up this campaign and its tactics as more reasons to hate the Chinese regime (sorry Tom Friedman) – even if you don’t approve of the consumption of pornography.
* I just don’t like giving the state the broad power to decide what is and what isn’t “pornographic” or “obscene.” Let’s not forget that even our government has a sketchy history doing so, including the arrest of “eccentric” presidential candidate George Francis Train for publishing some of the more colorful passages of the Bible! I also agree with what “A leap at the wheel” said in the comments section for Sven’s post: “I would also be concerned with giving the government (or a private agent that can be brought to heel with a subpoena or threat from a senator) a big list of people who consume unpopular speech.”
PILEUS 
I think worrying about the creation of a list of people who opt-in is a very legitimate one. There might be a technological/legal end-around to this, but then there is always an end-around to the end-around.
But remember that ISPs can already track internet usage without much trouble and the government can already subpoena such data. So I’m not convinced that the opt-in approach is that big of a deviation from the status quo, at least in terms of the objections you bring up.