penciling_in writes "During the 2+ weeks for which Site Finder was operational, a number of ISPs took steps to disable the service. A study just released reveals the details and analysis, including specific networks disabling Site Finder during its operational period. For example, the study reports China blocked the traffic at its backbone, and Taiwan's Chunghwa Telecom and Korea's DACOM also disabled the service. US ISPs have been slower to act, but US ISP Adelphia disabled the service September 20-22 before re-enabling it on September 23."
That link is a summary; or cut straight to the study itself