Sina and HTC China co-promote HTC One special model for Sina Weibo.
They prepared two type devices, and one of them is HTC One S, another is HTC One V. Basically these two devices are almost as same as world wide model of them, but main different point is a Sina Weibo hardware button.
When user push on the Sina Weibo hardware button, Sina Weibo is started. And if user push on this button when they use Web browser, the link of this page is put on Sina Weibo tweet page.
Sina and HTC also co-released special model named "Weike" last year.
Sina Weibo would like to increase their mobile user, and HTC also would like to increase their user and market share, so it may be they had a community of interests.
Baidu and Tencent already released their own Android custom ROM, and Baidu co-released their special Android devices with Changhong.
There is a lot of various actors in Chinese mobile industry, so it will be more exciting and interesting more than now :)
Original article => HTC official account on Sina Weibo