What's The Difference Between Www.yiiframework.com And Www.yiichina.net?

As the title says, what’s the difference between www.yiiframework.com and www.yiichina.net? They seem to be very similar websites. Why two sites?

The www.yiiframework.com is the official Yii website address.

I beg to differ:

whois.net/whois/yiichina.net

whois.net/whois/yiiframework.com

If you look at the Google’s +1 button, then on the yiichina.net domain it’s bigger, than on yiiframework.com.

So is yiichina.net an unauthorized copy or something? Why are there two nearly identical sites?