There's been much speculation about whether Yahoo/Microsoft would back Google's bold stance in the face of Chinese hacking and censorship of search results in that nation. The stakes just got raised:

The Yahoo e-mail accounts of foreign journalists based in China and Taiwan have been hacked, according to a Beijing-based press association.
Rival Google has been involved in a high-profile row with the Chinese government following similar cyber-attacks against Gmail accounts.
The Foreign Correspondents' Club of China (FCCC) has confirmed eight cases of Yahoo e-mail hacks in recent weeks.