On my Air China flight into Beijing one month ago, the inflight movie was The Social Network. It's a great movie, but it was pretty hard to understand because they kept bleeping out the word "facebook" whenever the characters mentioned it.
Okay, so that last part isn't exactly true, but what is true is that the Great Firewall of China is really annoying. Facebook, YouTube, Twitter, most blog sites (including this one) are out of the question unless you have a VPN program to skirt around the Wall. Then there are websites that sometimes you can access and sometimes you can't access depending on how the Wall is feeling that day, it seems, or based on where you're accessing from. It seems that the internet in my apartment is much more willing to access Google sites than the internet on computers in Tsinghua University. Given Tsinghua's close ties with key political bigwigs, that might not be such a surprise.
I've talked to some Chinese people about it, and they don't seem to mind it so much. After all, there's many Chinese versions of Facebook, YouTube, Twitter, and blog sites out there already, so there's no reason the typical Chinese web user would pine for using foreign versions of the websites they already have at home, in Chinese. If you ask the average American how they would feel if RenRenWang or Youku were blocked from them, they'd probably not even have realized that they had access to those sites in the first place.
The commonly stated reason why the Chinese government blocks all these foreign websites is because they can't keep tabs on potential dissidents or the otherwise unauthorized organizing of people. And that's a reasoning that certainly easy to accept. One of the most noticeable aspects of Cuba, which I visited just before coming to China, was just how deeply the government was afraid of its own people, and there's no reason to think that China should be much different. It seems that without procedural outlets of participatory government, access to justice, elections, etc., the major for people to make their voice heard is through protests or violent opposition. And so the government, realizing this, lives in constant fear of its people and tries to suppress interactions it deems out of "harmony."
But I met an American interning at Baidu, the Chinese answer to Google, who said that the most surprising thing about her experience has been just how little the government interferes with the day to day operations of the company. So maybe it's more economics than politics that is behind the Wall. After all, this is a country that limits the number of foreign films that can be shown in theaters, and requires many foreign companies to basically hand over their patents and trade secrets after a set grace period of domestic operations. So just as the real Great Wall was built to protect the interests of Han dynasties from nomadic tribes for hundreds of years, the Great Firewall might just have been built to protect the interests of domestic companies against foreign competition.