China has blocked Twitter and Hotmail:

Access to the popular social networking service Twitter and email service Hotmail was blocked across mainland China late on Tuesday afternoon, two days before the twentieth anniversary of a bloody crackdown on Tiananmen Square.

Indignant users filled chatrooms with protest, after access to Twitter was denied shortly after 5:00 pm (0900 GMT) on Tuesday.

"The whole Twitter community in China has been exploding with it," said Beijing-based technology commentator Kaiser Kuo.

"It's just part of life here. If anything surprises me, it's that it took them so long."