WPSauce reports that for the past 3 days Chinese users on many of the big ISPs there are having trouble accessing the Windows Phone 7 marketplace.
He was however able to access Marketplace fine when using a WIFI hotspot connected via VPN to USA, suggesting that Marketplace was being blocked by Chinese ISPs.
The Android Market apparently had the same issues in the past, forcing Motorola to ship their own custom market for Chinese phones.
It is not known as yet if this blockage is by accident or on purpose or how long it will last, but such a geographic fracturing can certainly not be good for Marketplace.
Read more detail at WPSauce here.