Weibo(微博) marketing makes any effect on search engines?

The Answer is YES, now.
Now it seems that contents of the Sina Weibo and Tencent Weibo appear in Baidu search results from November 2011.  It means that the promotion on weibo work effectively  also on SEO, and  will significantly affect future promotion strategies in China. The  algorithm to search results is unknown yet, but we expect to become more and more evident in future by trial and error.