Chinese workers walk out from the Alibaba head office building in Hangzhou, in eastern China's Zhejiang province on May 21, 2012.  Alibaba, China's top e-commerce player, will re-purchase a 20-percent state in itself from US portal Yahoo! for at least 7.1 billion USD, the companies announced.      CHINA OUT      AFP PHOTO        (Photo credit should read STR/AFP/GettyImages)