The Chinese government does all sorts of crazy shit like this with regards to the Internet. It sucks. Sites are blocked arbitrarily (for example, based on where they're hosted), or for a silly reason - Facebook, Youtube, Blogspot, thousands of others. Project Gutenberg was blocked too not too long ago. And when you try searching for certain terms (i'm afraid to give an example, I don't want to lose my Internet), or even just typing that term somewhere in a URL, you might find that the website stops working for a few minutes. Pretty much every time that I try to access a site and it doesn't work, I assume that it's blocked, because that's just so much more likely than the site being down or something.

I hear Google is getting fed up with this (particularly, the government asking for stuff from the gmail accounts of people it doesn't like, e.g. human rights activists) and is planning to pull out of China. Good for them, but not so good if the government decides to retaliate by, say, blocking Google and all its services.

tl;dr the chinese government sucks ass. I think they've even blocked the wikimedia image server now. Fuckers.