Don't know if you know they now, some Gmail was hacked by the Chinese, despite claims of innocence. You know they did it, I know they did it, and they know we all know they did it. With that settled, it's now known that Yahoo Mail as well as Hotmail were also in similar ways.
This Macworld post diplomatically did not mention Beijing by name as the perpetrator until near the end of the post but that their choice. Having said that, the Google mail accounts of US officials, journalists, and activists were the main target. I reckon gaining access to these same category of people is the same reason for the Yahoo and Hotmail attacks.
And chances are, if you're reading this, you probably are just an average mobile warrior like me and not an ambassador something like that. Still, it makes sense to change your passwords and such.
As a matter of fact, changing the passwords to all your online accounts is a prudent practice, even if you're not a member of the press or a freedom fighter living in a totalitarian realm.
More at Macworld.