Yahoo is not an ISP it is an e-mail provider in this case. China has its own ISPs, which it can control as it wishes.
I am not aware of any western ISP that "works with China"................they do not have Chinese users and have no prospects of making any money out of the place anyway. Also foreign participation in Chinese telecommunications is forbidden by law.
If any blocking goes on, it will be us blocking Chinese ISP ranges, given the amount of scam and spam that comes out of the place.;)
http://www.apnic.net/mailing-lists/a.../msg00008.html
