Adam has a nice post summarizing the recent Forrester report here. I was interviewed for this report and it reflects much of what I and my company have been saying about social media in China for years. Not much new, but nice to have some good stats to support.
1) social media in China is mainstream
2) creating content is more common than in the West
3) BBS discussion forums trump social networks
4) social media users have higher incomes, education, and consumption levels, compared to non-users.
For key graphic, compare levels of participation for social media in China vs. US: