Two years ago, when I was in college, I usually read the New York Times in the morning. Then one day suddenly I found New York Times was blocked. I decided to use proxy to log in my Facebook to figure out why our government blocked New York Times.
Some foreign friend and my Chinese friends who studied in America informed me a breaking new.
New York Times was not just post a normal family tree. The whole article describe the Wen family empire in detail including each family member's wealth, which was a very sensitive issue in China. Premier Wen won with a clean image and promise to dealing with corruption, finance and the economy.
Live coverage on breaking news events has been a routine method in major world media like CNN and BBC, which however is a brand-new thing in China. Moreover, such news were exactly offend China center government's sensibilities.
The reasons why China blocked social medias like Twitter and Facebook are multifaceted. First, these media always could generate some so-called rumor in China. Second, these social median could spread news in very fast speed which is really difficult for government to censor them. Third, officially, the Chinese government permit watchdog journalism, known as "supervision by public opinion," but in practice new outlets are wary of offending local party official.
Here is an example:
China quake school critic receives one-year sentence-group
And all the social medias, which are not under control of Chinese government, will never get chance to get approved to enter China market.