It turns out that Microsoft is censoring their Chinese bloggers in the interest of cultivating a relationship with the Chinese government. This is an American company limiting one of their customers' free speech.
Robert Scoble, the Microsoft Geek Blogger, is dismayed. He provides all the info you need to follow this story.
I can't say I'm surprised, but if American companies are cowtowing to the Chinese in order to make a buck, I can't say I'm in agreement. Sadly, I own Microsoft stock.
edit: follow-up: Scoble expounds upon the situation here and here