Totally agree. It was very smart to restrict Google and block Facebook, Twitter and Youtube to nurture our domestic counterparts. Now we have Sina weibo, Renren, QQ, tudou etc that are flourishing. Alibaba's Taobao is the largest online shopping site. I cannot imagine if those American firms captured the huge Chinese market while our internet companies were in infancy, not only economically, but politically.
On second thought, I think foreign companies might have hard time penetrating into Chinese market since Amazon failed miserably due to localization problem and English ability in general population. Even without restriction, Youtube Facebook Twitter wont gain popularity in China. Even in gaming, there are now two separate worlds, Chinese market and rest of the world. I guess lack of English ability sometimes is a bless for domestic companies.