Microsoft reportedly opened up Sina Weibo integration into the People Hub for for some random Windows Phone 8 devices. From WPCentral:

Sina Weibo is a microblogging service, which works just like Twitter on almost every aspect, except for:

It has over 300 million Chinese users, many times bigger than the Chinese-speaking population on Twitter.
And more importantly, it's not blocked by the Great Firewall.

Sina Weibo in People Hub works much like Twitter too. Windows Phone 8 users will supposedly be able to, when Microsoft finally finishes testing, post new tweets, retweet or reply, and share pictures to Sina Weibo directly through People Hub and the Me tile.

Microsoft flipping the switch for Sina Weibo's integration into the People Hub