A few of those changes are:
• Xbox Live functionality will be removed completely
• The Chinese version of Twitter and Facebook, WeiBo and RenRen respectively, will used to replace Twitter and Facebook, which are both blocked in China
• Search results will be a hybrid of traditional Bing results and BaiDu results (BaiDu is China’s number 1 search engine.)
It is not currently know if the Chinese Marketplace will be operational at the time of the Tango release. Additional details are expected to arise at Mobile World Congress 2012 and at an event in Beijing, China that is rumored to occur during the 3rd week of March. It is anticipated that several OEMS such as HTC, Nokia, ZTE, and LG will be at the Beijing event to showcase Tango-powered devices.
source: WPDang via WMPowerUser