Twitter will work with Chilling Effects, an Internet freedom advocacy website that compiles content take-down notices, to publish take-down notices. Such a practice would make it difficult for Twitter to operate in China, where Internet executives say prohibited keywords are treated like state secrets. The company…said [the measure]…would not be a solution for all [countries]. Some countries "differ so much from our ideas that we will not be able to exist there," the post said, an implicit reference to countries such as China that have banned Twitter…[M]ost microblogging users in China now use Chinese services, including by Sina Corp. and Tencent Holdings Ltd…These websites have grown quickly and collectively have hundreds of millions of user accounts, despite censoring content, and new regulations that require users to register for their services using real-names. [also refers to Google] (Wall Street Journal - subscription required)